Move setting variable init to load functions

This allows us to fall back properly when enabling/disabling mods that
don't set these values.
Don't autopickup items dropped by the player

Fixes #917
Merge pull request #930 from dorkster/autopickup

Don't autopickup items dropped by the player
Merge pull request #929 from dorkster/fixes

Move setting variable init to load functions
Remove duplicate declarations of background in Menu subclasses
Clean up SDLRenderDevice

* Add screen and titlebar_icon to SDLRenderDevice init list
* Reduce scope of some variables in scaleSurface()
Move tip_buffer to init list of TooltipData copy constructor
Remove unused alpha functions from SDL_gfxBlitFunc
Merge pull request #933 from dorkster/static_analysis

Fix some bugs found by cppcheck
Remove hard-coded instances of "maps/" when loading map files

Closes #894
Merge pull request #935 from dorkster/intermap

Remove hard-coded instances of "maps/" when loading map files
AnimationSet: use while loop instead of do-while
Loot: don't use animation, which may be possible freed.
Merge pull request #937 from stefanbeller/smallfixes

Smallfixes
Prevent moving around Sprites via std::vector operations

This removes the need for the keep_graphics flag.
Remove Sprite copying from GameStateCutscene

This changes image loading a bit. Instead of loading images when
creating the game state, images are loaded when creating each scene.
Don't copy Sprite of NPC portrait to MenuTalker

Usea pointer instead. This removes the need for keep_graphics in the
Sprite class.
Remove keep_graphics flag from Sprite class
Merge pull request #938 from dorkster/keep_graphics_removal

Remove keep_graphics flag from Sprite class