Full regex mode for jsdoc_custom_args_hook

[davidosomething]

• ADDED g:jsdoc_custom_args_regex_only config boolean
• ADDED support for matching against full regexes
• ADDED documentation

E.g. for

function myfunc(_isPrivateBoolean, isanother) {
}

the settings:

let g:jsdoc_custom_args_regex_only = 1
let g:jsdoc_custom_args_hook = {
                      \   '^_\?is': {
                      \     'type': '{Boolean}'
                      \   },
}

will yield

/**
 * @param {Boolean} _isPrivateBoolean
 * @param {Boolean} isanother
 */
function myfunc(_isPrivateBoolean, isanother) {
}

addresses #47 in a backwards compatible manner

[heavenshell]

Thx for pull request!
I'll look into it in this week end.
Little bit busy... 😢

[davidosomething]

Going to reopen this in a dev branch #51