Benchexec

- BenchExec moved to https://github.com/sosy-lab/benchexec
- Fix several bugs in table-generator introduced in version 1.3.
- BenchExec now creates fresh empty directories for $HOME and $TMPDIR
of all runs, and removes them afterwards.
- table-generator now transparently supports result XML files as input
that are compressed with GZip or BZip2.
- benchexec now reports some more information as status when a tool crashes,
e.g. whether it segfaulted or aborted, and what the exit code was
(previously this was only done for some tools).
- If a tool produces a result but still violates a resource limit,
this is now shown in the status (but still counted as timeout / out of memory).
- Added dummy tool "calculatepi" that needs no input files and no installation,
but can be used to create some CPU load and test benchmarking
(it calculates Pi up some arbitrary number of digits using the tool "bc").
- Renaming "tool wrapper" to "tool info".
This is mostly an internal and documentation change, but the utility
`benchexec.test_tool_wrapper` is now named `benchexec.test_tool_info`.

- Fix core assignment on AMD Bulldozer/Piledriver Opterons.
- Measure and report CPU time usage per core
(hidden by default in tables, use `table-generator --all-columns` to show).
- Parameter `--user` allows executing benchmarks under a different user
(cf. https://github.com/sosy-lab/benchexec/blob/master/doc/separate-user.md).
- Performance improvements for table-generator,
including parallel processing of input and output files and statistics.
- HTML Tables support filtering rows by task name.
- Improved statistics in HTML tables: median is now the arithmetic median,
unnecessary rounding removed, standard deviation added,
and missing results are not counted as "0" but ignored in calculation.
- New utility for testing tool wrappers, making it easier to add support
for new tools.
- Several new modules for integration of various software verifiers.

- BenchExec now records whether TurboBoost was enabled during benchmarking.
- Updated SV-COMP scoring scheme to SV-COMP 2016.
- Support new property 'no-overflow' for SV-COMP 2016.
- Several new modules for integration of various software verifiers.
- Some improvements to CPU-core assignment.

- HTML tables produced by table-generator now have a header that stays
always visible, even when scrolling through the table.
- A Debian package is now created for releases and made available on GitHub.
- Small bug fixes.

- Multiple runs for the same file can now be shown in the table in different rows
if they have different properties or ids.
- Helper files for generating scatter and quantile plots with Gnuplot added.
- Doctype declarations are now used in all XML files.
- Statistics output at end of benchexec run was wrong.

- Allow to redirect stdin of the benchmarked tool in runexec / RunExecutor
- Fix bug in measurement of CPU time
(only occurred in special cases and produced a wrong value below 0.5s)
- Improve utility command for checking cgroups to work around a problem
with cgrulesngd not handlings threads correctly.