Remove NullGrammar class now in first-mate

src/null-grammar.coffee

@@ -1,23 +0,0 @@
-Token = require './token'
-{Emitter} = require 'emissary'
-
-### Internal ###
-module.exports =
-class NullGrammar
-  Emitter.includeInto(this)
-
-  name: 'Null Grammar'
-  scopeName: 'text.plain.null-grammar'
-
-  getScore: -> 0
-
-  tokenizeLine: (line) ->
-    { tokens: [new Token(value: line, scopes: ['null-grammar.text.plain'])] }
-
-  tokenizeLines: (text) ->
-    lines = text.split('\n')
-    for line, i in lines
-      {tokens} = @tokenizeLine(line)
-      tokens
-
-  grammarUpdated: -> # noop