style: enforce spaces after keywords, add spaces

Moving the `requireSpaceAfterKeywords` rule to jscs with associated changes.

Is it preferred to explicitly specify the keywords in an array?

Or use `requireSpaceAfterKeywords = true`
which is equivalent to `requireSpaceAfterKeywords = [ 'do', 'for', 'if', 'else', 'switch', 'case', 'try', 'catch', 'void', 'while', 'with', 'return', 'typeof', 'function'];`

Although it doesn't make sense for `function`.

cc: @caitp
+1