Update CMakeLists.txt

Add debugging flags for Nvidia's NSight tools
Update CMakeLists.txt

Made nsight debugging stuff work only for debug builds - previous CMAKE if statement wasn't working appropriately (was adding flag to release builds.)
Merge remote-tracking branch 'upstream/master'
-Wall only for gcc
Merge pull request #13 from bucienator/fixwarnings

-Wall only for gcc
Merge pull request #12 from msarahan/nsight_debug_flag

Nsight debug flag