(1) Checkers now have an _exec attribute, and an accessor getExec().
(2) CreateAndRegisterChecker() initializes _exec from an optional argument
'exec'. If this argument is missing, 'name' is used instead.
(3) Functions SyntaxCheckers_*_IsAvailable() are now dictionary functions.
(4) Functions SyntaxCheckers_*_IsAvailable() are now optional. When
they are missing, they are assumed to return executable(expand(self.getExec())).
(5) Argument 'exe' of function syntastic#makeprg#build() is now optional.
If this argument is missing, expand(self.getExec()) is used to set checker
executables.
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).
Version check: errorformat depends on the combination of node version
and CoffeeScript version. When run under recent nodes, only 1.6.2 and
newer produce errors we know how to parse.
Changed again "-t", this time to "-cp".
The -t flag will output tokens (and syntax errors if there are any) - it is quite a lot quicker than another alternative, -n, especially for large files.
No need to generate a file when linting, as the coffeescript compiler
will do that for you.
This has been tested with coffeescript 1.6.2.
Also: use options over flags for readibility
