Merge pull request #30 from DaveAckley/master

Logging window mostly
Merge pull request #31 from DaveAckley/master

Try out dlopen
Removed GridPanel.tcc
Removed GridPanel.tcc
Added MAKE_GUI make argument, possible mfmheadless gui build
AssetManager for SDL_Surface management, integrated into AbstractGUIDriver
AssetManager.cpp for member definitions
Merge pull request #32 from DaveAckley/master

ByteSource first round - ExternalConfig close to working
Merged ExternalConfig request
Fixed MQbar.h for newer g++
AssetManager grabs images from ~/.mfm/res/images
Togglable toolbox window with events and assets. Install with 'cp -r assets ~/.mfm/res'
Toolbox activated with [t], visual feedback for selecting tools
Basic pencil painting with Element_Wall . Moved assets to res/images
Motion painting and erasing
Bounds checking in GridPanel.h
Brush tool
Bucket fill tool
ToolboxPanel element selection
Can no longer fill with empty brush