Added support for #| foo |# style block comments.

This adds support for the following bracketed comment style : ```#| comments! |#```. Resolves issue #21.
```
(defun (foo a b)
       (+ a b #| foo |# 3))
```
This is also legal...
```
(defun foo
       #| (let ((x (: io read_file 'bar)))
               (do-stuff x)) |#
               (no-really-do-stuff (: gief 'bar)))
```
As has been covered in every mention of this topic, this is not legal:
```
(defun foo
       #| (let (#| get info |# (x (: io read_file 'bar)))
               (do-stuff x)) |#
               (+ 3 3))
```
No nested comments for you!

I'm not sure if/how to add tests for this or if there is something I am missing.. :)