Remove `wrap`
Add Gemfile and Gemfile.lock
Extract some code as `token_grep` to write tests
Add a test to make sure `token_grep` works fine with multiple tokens

It fails.
Sort token_positions by begin_pos to highlight them correctly

Because tokens latter in code can be superior in AST and
`search` returns nodes in order of superiority,
it is necessary to sort token_positions by its position
to highlight them correctly.

ast = Parser::CurrentRuby.parse("a.b")
  # => (send
  #      (send nil :a) :b)
Update README

* Update sample output
* Add Install
* Remove NOTE
* Add Current Restrictions