Work in progress on implementing #98.
Collect errors/warnings from compile:forms/2 properly.

Reverted the out_dir -> outdir option rename.
Move compiler_options more into the background as an advanced option.
Clean up generated code.

Fixes #109.
We had too many warnings from the generated code on for loops,
in order to continue working on #98.
Add tests for error reporting.
commented R16B03 in .travis.yml for now..
Merge branch 'pu-98'

Close #98.