Make init_movit() return a true/false error value.

This allows clients to programmatically enable/disable Movit usage
as needed on very old platforms.
Move everything into “namespace movit”.

This is a pretty hard API break, but it's probably the last big API
break before 1.0, and some of the names (e.g. Effect, Input ResourcePool)
are really so generic that they should not be allowed to pollute the global
namespace.
Fix a typo.
Use abort() on check_error() failure.

This makes it much easier to trace them down in a debugger.
Check GLSL program link status, for better error reporting.
Use GLSL 1.30-style attributes for the main shader.

This is in preparation for removing fixed-function use altogether,
for OpenGL 3.2+ core context support.
Make the initializing functions also drop fixed function usage.
Ignore libtool files in .gitignore.
Fix dependencies for .lo files.

Dependencies were unfortunately de-facto broken after introduction of libtool,
causing much head scratching. Now fixed.
Add a simple luma wipe transition.

Conflicts:
	Makefile.in
Fix some formatting messups.
Ignore .ld files.
.gitignore more unit tests.
.gitignore lots of libtool stuff.
Make the COVERAGE variable into an --enable-coverage configure flag.

This makes a lot more sense, since it controls compilation options.
More tweaks to the .ld generation.
Properly install texture1d.frag, which is needed during init.
In the README, document that we have luma mix.
Add a inverse flag to LumaMixEffect.

This is mainly a convenience so that you can change e.g. a left-to-right
wipe into a right-to-left wipe without having to add a separate inverting
effect to the luma. Suggested by Dan Dennedy.
Fix typo in luma_mix shader.