Do not suppress the compile error code when generated sourcemaps

Currently the error return code of output can be suppressed if
sourcemaps are generated. Even if this is can not be the case because
if the compiler fails there may not be any source map data, it at least
looks suspect.
Merge pull request #85 from rototor/compile_file_dont_suppress_errorcodes

Do not suppress the compile error code when generating sourcemaps