Check template checksums also for binaries.

When compiling a template not from file (e.g. from a binary value),
keep track of the checksum the same way as is done when compiling templates on file.

Moved default value for compiler_options back to the record definition.
Adopt CONTRIBUTING from rebar.
Add check and dialyze targets (#111)

But don't fail a build on dialyzer warnings (not yet at least).