Starting tileset implementation.

- Adding fatal errors in resource exception constructors for now.
Merge branch 'master' of https://github.com/peter-clark/lifeline

Conflicts:
	src/LE/engine/tilemap_component.cpp
Added build directory to ignore.
Merge remote-tracking branch 'origin/hack'
Corrected abuse of auto in sample code.

- Now only using when type is already listed, for iterators, and for containers.