Delocate

- Add some useful flags to `delocate-add-platform`
- Refactoring

- Add utility to add platform tags to wheel contents and name
- Add more general wheel context manager
- Some refactoring for neatness

- Add utilities and script to apply a patch to a wheel
- Add utilities and script to test for architectures in libraries and
require named architectures
- Docstring fixes and refactoring

- Set `install_name_id` for copied libraries to be unique to this package.
OSX uses the `install_name_id` to identify a library uniquely on the
system. If two libraries have the same `install_name_id` when loaded into
the process, then OSX will raise an error unless their compatibility number
matches. Delocate now sets the `install_name_id` to be more or less
unique with a Python process at least. This means OSX won't raise an error
if you have two different libraries in two different packages (e.g hdf5
libraries in `h5py` and `pytables`.
- Turn on compression for creating wheel zip files. Previously we were zipping
without compression (because MB didn't know that was the default).
- Raise an error if delocating attempts to copy two different libraries with
the same name (therefore overwriting one with the other).
- Add command and functions to do architecture fuse between two different
wheels. This can be useful when you have to build a 32-bit and 64-bit wheel
separately. In that case you can fuse the two wheels making fat (combined)
architecture libraries, using `delocate-fuse`. Add supporting routines
for detecting architecture of libraries and fusing libraries with different
architectures.
- Add use of `os.path.expanduser` to specified output wheel directory for `delocate-wheel` script.
Now flag input like `delocate-wheel -w ~/wheels some_wheel.whl` will correctly output to `$HOME/wheels`.

- Switch to using just `loader_path` rather than a combination of
`loader_path` and `rpath` for pointing to relocated libraries. Using
`rpath` was giving some errors of form:

"install_name_tool: changing install names or rpaths can't be redone
for: libsomething.dylib (for architecture x86_64) because larger updated
load commands do not fit (the program must be relinked, and you may need
to use -headerpad or -headerpad_max_install_names)

Presumably because `rpath` had been zero length before we got to the library.

- Add flag to display depending libraries as well as the libraries a tree /
wheel depends on.
- Use canonical paths for depended and depending library paths, including
following symbolic links. This means that two links pointing to the same
file don't appear to be two different libraries, causing an error when
copying the second into the directory containing the copied libraries.
- Don't raise an error when delocating a wheel that was previously delocated
(MinRK)

Bugfix release

- Rewrite wheel RECORD file when writing wheel. Delocated wheels were
breaking `wheel unpack` command.