Apparently on some BSD systems man pages go to /usr/man instead of /usr/share/man.
It's too complicated to keep track of all the nuances of Linux distros so package maintainers can simply override the default via a $FONTTOOLS_MANPATH env variable
Fixes#84
It's not a good thing that we build different wheel packages (with/without data_files) according to the platform we build them with.
After all, these wheels are meant to be "universal".
Even when manpages can't be used on a target platform (e.g. Windows), their mere presence should not do any harm; they are simply copied to a 'share/man' folder relative to the python prefix. On Unix systems (Linux, Homebrew, etc.) this is usually `/usr` or `/usr/local`, so `man ttx` just works (TM).
Note that other popular python tools like IPython or Sympy also install manpages the same way we do here with ttx, and they do that unconditionally for all platforms.
As regards issue #796, whereby attempting to `sudo pip install fonttools` fails because the manpage file is copied to a SIP-protected location on OSX El Capitan and above:
Users who still wish to install fonttools globally with sudo (and are not scared after googling 'why sudo pip is bad'), can still use the '--install-data' option of setup.py install to modify the data_files base installation directory.
If you install with pip (recommended over `python setup.py install`), you can use --install-option to pass through installation options to setup.py (which is run by pip when installing from source).
For example, to install man pages to /usr/local/share/man/man1/*.1 you could pass "/usr/local" as the base directory for --install-data, like so:
sudo -H /usr/bin/python -m pip install --install-option="--install-data=/usr/local" fonttools
This makes sure we upload the same files to Github Releases and PyPI.
Currently we were building them twice, with the risk of different files
being uploaded to the two repositories.
