Add support for binary file compilers

[kavika13]

Currently the pipeline reads files from the filesystem as UTF-8 before passing the data to compilers, and there is no option to read in "binary only" mode.

I don't know if the factoring of the pipeline and how files are processed works with this, but it would be nice if a compiler could have a configuration setting to let the pipeline know it has to pass it data in binary format.

Currently the workaround is to supply the compile function signature that takes the data, path, and callback, and then re-open/re-read the file in your compiler.

Example use case: HTML 5 game that uses binary assets, converting them to javascript data at compile time.

[kavika13]

This is a feature request.