More malloc checking

Don't crash if running out of memory when allocating per-glyph data
during shaping. Also some fixes to initialization.

The caller of ass_fontconfig.c/match_fullname() actually handles a NULL
return value correctly.
Add Travis-CI integration
travis-CI: configure needs to be generated
Travis-CI: sigh

OK, so autogen.sh doesn't run configure.
Travis-CI: another attempt at making it work

Switching to OSX, because homebrew is more uptodate than
Ubuntu Ancient LTS, which is what Travis uses on Linux.
Travis-CI: another attempt at making it work (2)
Travis-CI: add Coverity scan
Travis-CI: add coverity_scan branch to enabled branches
Travis-CI: minor changes

Strictly use the default compiler, but this probably has exactly the
same effect as using the "gcc" entry.

Do a parallel build.
Travis-CI: make Coverity scan work

Also add the obnoxious Coverity badge to the README
(thanks to torque for the reminder).
Fix broken memory leak check in legacy API

This was a check for the realloc() call, but the result was never
used in the success case - which makes no sense.

Doesn't really matter, because it's the legacy charset code which
hopefully is not used by anyone.

Found by Coverity.
Travis-CI: Coverity requires a notification email address

Or at least it looks like it does.
Leave spline evaluation to rasterizer
Fix incorrect closing of last drawing contour
Flip coordinate system in rasterizer
Replace FT_Outline with ASS_Outline