Travis CI:
Replace GCC4.9 64-bit with GCC7 64-bit.
Replace GCC5 32-bit with GCC7 32-bit.
Move 64-bit to top of matrix so it gets built first (ccache doesn't work
on the 64-bit build and I don't know why (it works locally), so it takes
the longest to build).
AppVeyor:
Add VS2017 build job.
Enforce CRLF line endings so Windows users can actually edit using
notepad.
Build buildbot.xml ReleaseAll target with both VS2013 and VS2015.
Create 7zipped build similar to what the buildbot makes.
Jonathan Li