Add parsing parameters method, and verbose them if verbose is specified.

Still need to take all of them into account though.
Add some logs displayed if verbose is turned on.
Manage the type,t option

Allow numerics in types (still need to correct issue #1).
Allow multiple types:
 - By specifying multiple types separated by ':'.
 - By using multiple times the -t, or --types, option.
Manage the k,h options to display size in kilobytes or in human readable format.

A new function pretty_size have been implemented to format the size into human readable format.
-b or --bytes options has been removed, as it is not relevant to measure file sizes into bytes (due to minimum cluster size of hard-drives).
Correct usage message, options verbose, version and help are implemented.
Change the print format for the results (du command like).

Use printf to left pad for sizes in human readable format, and right pad for classic format.
Also write the number of files for the extensions.
For example: "423M foo (56)", mean that there is 56 files having the foo extension for a total size of 423 megabytes.
Add a final line for the files not having regular extensions.

It will print a line like this: "8K OTHERS (1)", meaning that there is one file of 8 kilobytes not having a regular extension.

It was a little tricky to find a way to launch the 'find' command with dynamically generated parameters, finally eval seams to works fine.
Use 'local' keyword to use real local variables in functions.
Change the 'version' output, add the date of the release.
Fix issue #2, from now on the pattern for an extention is any alphanumeric character, plus underscore and dash.
Release v0.2