Started work on grass resolution

Grass supplies static method to grab a low resolution view of grass
growth
Updated MarkovGeneration to support in place

You can now specify MarkovGeneration to use an in place matrix instead
of making a copy first.  This can be useful for certain effects, or if
making a copy is not needed and you want to speed things up.
Fixed critical bug in Gallimimus.as

The condition function did not return a value on all execution paths.
Fixed conflict and removed working code
Added tile types lake & bush and tile Bush class

And updated legend in MarkovModel class
Merge pull request #10 from mentatzoe/master

Added tile types lake & bush and tile Bush class