Add a preferences menu item for the JSLint extension that allows to set global options for JSLint

[JoachimK]

Should support all the options on jslint.com.

E.g. open a dialogue with a checkbox for each of the options and save them in the preferences store.

Options can then be given to JSLint as config object in the second parameter of the JSLint() call.

JSLint(codetoCheck, options)