Minor compatibility fixes
Merge pull request #918 from igorko/master

Minor compatibility fixes
Fix loading cutscene images
Merge pull request #919 from dorkster/fixes

Fix loading cutscene images
Use separate files for layer definitions and hero options
Don't reload mods on every settings change
Merge pull request #922 from igorko/bugfixes

Don't reload mods on every settings change
Don't add default mod to list twice
Merge pull request #924 from igorko/master1

Don't add default mod to list twice
Check for default mod before searching mod directories

Prevents "Mod default not found, skipping" message.
Merge pull request #925 from dorkster/fixes

Check for default mod before searching mod directories
Merge pull request #920 from igorko/master

Use separate files for layer definitions and hero options
Don't create new surface/texture when copying Sprite
Remove setAlpha() and setColorKey()

These functions were being used to no effect. We set the alpha for blank
surface using fillImageWithColor(). The only place we used setColorKey()
was on a surface created with createSurface(), which sets the color key
by itself.
Make sure m_ttf_renderable's surface is set to NULL

This prevents a double-free case.
Merge pull request #926 from dorkster/fixes

SDLRenderDevice fixes
Merge remote-tracking branch 'upstream/master' into sdl2