Allow for all options in CompileFromSourceString (#823)
Allow for all options in CompileFromSourceString (#823)

Shares core logic between Compile and CompileFromSourceString to
allow for some previously unsupported options in
CompileFromSourceString such as support for input languages
other than OpenCL and outputting to a file.

google/clspv,google/clspv,google/clspv,google/clspv,google/clspv