Pwntools-elf-only

- [1198][1198] More compatibility fixes for pyelftools==0.25, and pin Sphinx<1.8.0 since it causes testing errors
- [1191][1191] Fix compatibility with pyelftools==0.25
- [1159][1159] Fix check for `/proc/.../status`
- [1162][1162] Fix broken package versions
- [1150][1150] Fix exception raised when a cache file is missing
- [1156][1156] Fix ROP gadget selection logic involving `int` and `syscall` instructions
- [1152][1152] Fix QEMU LD_PREFIX calculation (wrong parameter passed)
- [1155][1155] Use Ubuntu Trusty for all CI builds
- [1131][1131] Add "libc-" to libc prefixes in `process` tubes
- [1125][1125] Fix a typo
- [1121][1121] Fix tests which were broken by an upstream Sphinx change
- [1104][1104] Add `DynELF.dump()` for dumping remote ELF files
- [1101][1101] Set `context.os` via `context.binary`, useful for Android exploitation
- [5fdc08][5fdc08] Work around broken `pidof` on Android
- [63dfed][63dfed] Print warning when Corefile deletion fails instead of throwing an exception
- [1094][1094] Make hexdump output alignment more consistent
- [1096][1096] `flat()` and `fit()` are now the same function

[1198]: https://github.com/Gallopsled/pwntools/pull/1198
[1191]: https://github.com/Gallopsled/pwntools/pull/1191
[1159]: https://github.com/Gallopsled/pwntools/pull/1159
[1162]: https://github.com/Gallopsled/pwntools/pull/1162
[1150]: https://github.com/Gallopsled/pwntools/pull/1150
[1156]: https://github.com/Gallopsled/pwntools/pull/1156
[1152]: https://github.com/Gallopsled/pwntools/pull/1152
[1155]: https://github.com/Gallopsled/pwntools/pull/1155
[1131]: https://github.com/Gallopsled/pwntools/pull/1131
[1125]: https://github.com/Gallopsled/pwntools/pull/1125
[1121]: https://github.com/Gallopsled/pwntools/pull/1121
[1104]: https://github.com/Gallopsled/pwntools/pull/1104
[1101]: https://github.com/Gallopsled/pwntools/pull/1101
[1094]: https://github.com/Gallopsled/pwntools/pull/1094
[1096]: https://github.com/Gallopsled/pwntools/pull/1096
[5fdc08]: https://github.com/Gallopsled/pwntools/commit/5fdc08
[63dfed]: https://github.com/Gallopsled/pwntools/commit/63dfed

- [1083][1083] Better error messages for `gdb` when `LD_PRELOAD` is incorrect
- [1085][1085] Add support for extracting Android `BOOTLDR!` images
- [1075][1075] Add support for detecting GNU Screen for `run_in_new_terminal`
- [1074][1074] Add support for running `pwntools-gdb` wrapper script instead of `gdb`
- [1068][1068] Work around very old OpenSSL versions which don't have sha256 support *AND* don't exit with an error code when trying to use it
- [1067][1067] Add `pwnlib.tubes.server` module, which adds a reusable `server` listener
- [1063][1063] Add support for labels in `fit()`, allowing dynamic contents to be injected. (This feature is really cool, check out the pull request!)

[1083]: https://github.com/Gallopsled/pwntools/pull/1083
[1085]: https://github.com/Gallopsled/pwntools/pull/1085
[1075]: https://github.com/Gallopsled/pwntools/pull/1075
[1074]: https://github.com/Gallopsled/pwntools/pull/1074
[1068]: https://github.com/Gallopsled/pwntools/pull/1068
[1067]: https://github.com/Gallopsled/pwntools/pull/1067
[1063]: https://github.com/Gallopsled/pwntools/pull/1063

- [1044][1044] Enhancements to ROP
+ Much better support for 64-bit Intel (amd64) ROP
+ ROP gadget selection is optimized to favor multi-pops instead of multiple single-pop gadgets
+ Added support for blacklisting byte values in ROP gadget addresses
- [1049][1049] Enhancements to `cyclic`
+ `context` now has two additional attributes, `cyclic_alphabet` and `cyclic_length`, which correspond to the arguments `alphabet` and `n` to `cyclic()` and `cyclic_find()` and related routines.
+ The motivation for this change is to allow setting the `alphabet` globally, so that any padding / patterns generated internally to pwntools can be controlled. The specific motivation is blacklisting values in ROP padding.
- [1052][1052] Enhancements for detecting `QEMU_LD_PREFIX` used by QEMU user-mode emulation for sysroots
- [1035][1035] Minor documentation changes
- [1032][1032] Enhancements to `pwn template`
- [1031][1031] More accurate `Coredump.fault_addr` on amd64
- [1084][1084] Fix broken tests due to `ftp.debian.org` going down

[1044]: https://github.com/Gallopsled/pwntools/pull/1044
[1049]: https://github.com/Gallopsled/pwntools/pull/1049
[1052]: https://github.com/Gallopsled/pwntools/pull/1052
[1035]: https://github.com/Gallopsled/pwntools/pull/1035
[1032]: https://github.com/Gallopsled/pwntools/pull/1032
[1031]: https://github.com/Gallopsled/pwntools/pull/1031
[1084]: https://github.com/Gallopsled/pwntools/pull/1084

- [1007][1007] Add support for setting a `gdbinit` file in the context
- [1055][1055] Fixes for `Corefile` stack parsing, speed up `ELF.string()`
- [1057][1057] Fix a variable name typo in `DynELF` logging which results in an exception being thrown
- [1058][1058] Fix an edge case in `ssh_process.exe`

[1007]: https://github.com/Gallopsled/pwntools/pull/1007
[1055]: https://github.com/Gallopsled/pwntools/pull/1055
[1057]: https://github.com/Gallopsled/pwntools/pull/1057
[1058]: https://github.com/Gallopsled/pwntools/pull/1058