Previously we were using "medium verbosity" with `-W1`. The reason for
this is because using full verbosity caused some bogus repeated warnings
to appear in rspec files.
Enable full verbosity again and filter out the bogus warnings.
Closes#290
* move the existing ruby checker to syntax_checkers/ruby/mri.vim
* add a skeleton checker for jruby
* load mri by default but add an option to specify which ruby checker to
load
This is in response to #185
