Fix bug where cursor could be freed more than once
Move sprite_t to dos_sprite_t
Add Travis CI configuration file
README: Add build status from Travis CI
Merge branch 'travis-ci'
sdl-video: Move sprite_t conversion to gfx.c

Sprite caching is moved to gfx.c as well.
sdl-video: Move all palette use to gfx.c
sdl-video: Move sprite masking to gfx.c
gfx: Merge sprite caches into single hash table
sdl-video: Merge all sprite drawing functions into one
Fix: include misc.h in gfx.h for uint definition
Merge branch 'gfx-sprite-move'
Abstracting graphics and data source

Set apart of basic and common functionality for graphics and data
source.
Merge branch 'Abstracting-graphics-and-data-source' of https://github.com/wdigger/freeserf into Abstracting-graphics-and-data-source