Initial commit of isNoData and isData macros.

Still need to figure out how to make those functions import nicely
with just `geotrellis._`. Aims to fix #624
isNoData and isData macros in geotrellis package

Converted all comparisons to their macro equivalent

z == NODATA                -->  isNoData(z)
z != NODATAT               -->  isData(z)
java.lang.Double.isNaN(z)  -->  isNoData(z)
!java.lang.Double.isNaN(z) -->  isData(z)
Added unit test for very strange compiler break.
Merged in upstream BitArrayRasterData fix
Merge pull request #639 from lossyrob/isNoData-macro

isNoData and isData macros