Generator: Fixed unused variable warning.
Coordinate Matrix: Added missing row_info_extractor kernel to OpenCL sources.

The function was apparently implemented, but accidentally not included in the program string.
OpenCL context: Program name is now also printed if a particular kernel cannot be found.
Block-ILU: Removed one unnecessary temporary, partially addressing issue #40

Still transposition of the block factors required, which is way too slow at the moment.