WIP: Use Mesa on Appveyor
FIX: Better testing
FIX: Skip bad mesa test
FIX: Fix font test
FIX: Update URL
FIX: Fix env var
FIX: 32-bit as well
FIX: Comment
FIX: Fix call
FIX: Revert to 64-bit only
ENH: Add 32-bit
FIX: Always try 64-bit?
FIX: Only use 32-bit
FIX: Fix check
Merge pull request #668 from Eric89GXL/mesa-win

ENH: Use Mesa on Appveyor