Move effect removal outside of effect processing loop.

Add -D_GLIBCXX_DEBUG to Makefile for debugging iterators
Fix wrong iterator use in Item_factory and fix signed vs unsigned warning.
put contents of burned items into temporary vector,

Add them to the map after the iteration over all items on that square is done.
This avoids invalidating the iterator.
fix bug in distance calculation.
Merge branch 'fix-iterator-related-crashes' of https://github.com/BevapDin/Cataclysm-DDA into merge
Merge branch 'fix-monattack.cpp' of https://github.com/BevapDin/Cataclysm-DDA into merge