NumberHandler is a shared mixin that provides automatic conversion of dates and prices into a sanitized format.

This adds missing tests to validate that the mixin functions as expected.

Closes reenhanced/real_hq_shared#1

LGTM given by: @codenamev

Squashed commit of the following:

commit d79812b64340efb95c7160db67c4d32259358d10
Author: Nicholas Hance <nhance@reenhanced.com>
Date:   Wed Jun 5 14:25:14 2013 -0400

    Refactor to use initializer

commit b139a79fe0679161ec7dbdb5e0481185d486c10a
Author: Nicholas Hance <nhance@reenhanced.com>
Date:   Wed Jun 5 14:17:14 2013 -0400

    another small update

commit 19f4aa4a8db60d1467ca329f01a5baabdcb61104
Author: Nicholas Hance <nhance@reenhanced.com>
Date:   Wed Jun 5 14:11:02 2013 -0400

    pull request updates

commit 76de0c49bc1029bd507c166efaa1702ab5e13b39
Author: Nicholas Hance <nhance@reenhanced.com>
Date:   Wed Jun 5 10:04:53 2013 -0400

    finishes tests

commit 919b8513e6f2da34d14a1c555ac096f7471eca63
Author: Nicholas Hance <nhance@reenhanced.com>
Date:   Tue Jun 4 18:11:16 2013 -0400

    AttributeMethods isn't required after all

commit 4ee3cc9eee12aa98cb8de1f280b9a55908262d6c
Author: Nicholas Hance <nhance@reenhanced.com>
Date:   Tue Jun 4 18:10:25 2013 -0400

    Adds missing files. I always forget that

commit db2257b1f032c7eb13baa020293fa287142a2e03
Author: Nicholas Hance <nhance@reenhanced.com>
Date:   Tue Jun 4 18:00:02 2013 -0400

    Phone numbers and a start on currency_numbers. Will finish this up tomorrow for maximum first impressions.

commit 28a3e43e6d0e0155beb7101bd83eb1aacaf37686
Author: Nicholas Hance <nhance@reenhanced.com>
Date:   Tue Jun 4 16:22:05 2013 -0400

    NumberHandler.sanitize_phone_number tests