Ruby: add reek style checker
Reek checker: cleanup.
Remove the avrgcc checker for Arduino.

According to #1173: "When the Arduino IDE compiles arduino files,
they're not just passed to avr-gcc -- there's some preprocessing that
happens".  This is the template problem, and syntastic doesn't have a
solution for it at this time.
Dartanalyzer can now return exit code 3.
Shut up vimlint.
FAQ: add a note about HTML Tidy for HTML5.
README: rephrase.
Discourage people from looking at the sources for user docs.
make golint report warnings instead of errors
Merge pull request #1255 from vincent-petithory/golint-warning

Golint: report warnings instead of errors.
Add support for maven customizations