Allow to run from the build directory even if it is not on the path
properly decode subprocess stdout/stderr as UTF-8
Added newlines that were mistakenly left out of print->sys.stdout.wriote() conversion in previous CL
Python 3:
- fixed error message comparison
- explicit list creation
Windows:
- forward/back slash annoyances
- added stdint.h with definitions for int32_t, int64_t
- compile_error_files and run_error_files were being appended to improperly
