Use the grammar's definition of nonWordCharacters

[Arcanemagus]

Unify all retrieval of the list of nonWordCharacters into a single function, and always pass a TextEditor and Point to this function, allowing it to use that point to get a ScopeDescriptor in order to get the list of nonWordCharacters specific to the language(s) at that scope.

Note:
The specs needed to be changed here as language-php doesn't include $ in the list of nonWordCharacters, so once this is implemented if you only select test from $test it will no longer be highlighted if the whole word selection option is enabled.

> atom.config.get('editor.nonWordCharacters')
"/\()"':,.;<>~!@#$%^&*|+=[]{}`?-…"
atom.config.get('editor.nonWordCharacters', {scope: ['text.html.php']})
"/\()"':,.;<>~!@#%^&*|+=[]{}`?-"

Fixes #183.