Make SyntaxCheckers_*_GetLocList() dictionary functions.
Pass a reference to the current checker to syntastic#makeprg#build().
Add an optional 'redirect' argument to CreateAndRegisterChecker().
Change the sh checker to use the new dictionary functions.
Add a new registry method getLocListRaw() (needed for the sh checker).
The errorformat for the RuboCop checker was missing the capture group
for the column number of the error/warning, which resulted in the
location list attempting to jump to 'filename.rb:80', which would
attempt to open a new file.
The solution was to add the "%c" to capture the column number of the
error.
