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

This adds support for the following comment style

(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
and never will be under the current implementation of the parser.

(defun foo
       #| (let (#| get info |# (x (: io read_file 'bar)))
               (do-stuff x)) |#
               (+ 3 3))

Nested comment blocks are not allowed and will error as a syntax error.
Add nicer parse error for nested comments.

The parser does not support nested block comments and the debate rages
on as to whether or not they are required. This is an improvement on the
existing support for simple block comments in that it provides a syntax
error and a line number when they are encountered.

I'm not convinced I've done it the right way but it's a state. :)
Fixing for awesome.

I ran some, albeit slightly contrived, benchmarks for the change from re:run/2
to string:str/2 and string:str/2 came out ahead. The gist of what I did
can be found here https://gist.github.com/mankyKitty/8558705.

Also removed the line number inclusion from the error message.

Everything is a lot cleaner now too!
Updated the comments and added example usage.
Renamed BINDIR to EBINDIR.
Added targets related to EXPM.
Added EXPM file.
Tweaked Makefile:
* removed useless BINDIR target (already exists)
* updated upload and get-deps targets
Added some feedback for the user.
Updated comment lines with single colon.

Per Robert's request; this makes working with Emacs easier.
Add dynamic exprs to the interpreter

These use the current environment when evaluating. It could be useful
when handling simple functions at tip-level. Also added to the
lfe_eval.lfe in examples and made it uptodate accessing the
environment.
Make compiler add source file name to compile info
Merge pull request #52 from oubiwann/update-gps-example

Updated the comments and added example usage.
Merge pull request #48 from oubiwann/add-expm-support

Add expm support
Merge pull request #51 from mankyKitty/add-bracketable-comments

Added support for #| foo |# style block comments.
Merge branch 'develop' of github.com:rvirding/lfe into develop
Merge branch 'develop' of https://github.com/rvirding/lfe into record-info-macro