PT-588 - Add petitions_homepage module to make /homepage configurable by site admin.

Add new petitions_homepage module:
 	new file:   modules/custom/petitions_homepage/README.txt
 	new file:   modules/custom/petitions_homepage/img/petitions_landing_btns_0.png
 	new file:   modules/custom/petitions_homepage/img/petitions_landing_hero.jpg
 	new file:   modules/custom/petitions_homepage/img/petitions_landing_rightrail.png
 	new file:   modules/custom/petitions_homepage/img/petitions_landing_wh_content_01.jpg
 	new file:   modules/custom/petitions_homepage/img/petitions_landing_wh_content_02.jpg
 	new file:   modules/custom/petitions_homepage/img/petitions_social_icons.jpg
 	new file:   modules/custom/petitions_homepage/img/petitions_tw_landing.png
 	new file:   modules/custom/petitions_homepage/img/petitions_video_thumb_new.jpg
 	new file:   modules/custom/petitions_homepage/img/petitionslanding_arrow.png
 	new file:   modules/custom/petitions_homepage/img/sprite-bg.png
 	new file:   modules/custom/petitions_homepage/img/tweet_retweet.png
 	new file:   modules/custom/petitions_homepage/petitions_homepage.admin.inc
 	new file:   modules/custom/petitions_homepage/petitions_homepage.info
 	new file:   modules/custom/petitions_homepage/petitions_homepage.install
 	new file:   modules/custom/petitions_homepage/petitions_homepage.module

Remove hard-coded /homepage content and related stuff from theme:
 	modified:   themes/petitions44/petitions44.info
 	renamed:    themes/petitions44/css/homepage.css -> modules/custom/petitions_homepage/css/homepage.css
 	renamed:    themes/petitions44/sass/homepage.scss -> modules/custom/petitions_homepage/sass/homepage.scss
 	renamed:    themes/petitions44/sass/petitions-grid.scss -> modules/custom/petitions_homepage/sass/petitions-grid.scss
 	renamed:    themes/petitions44/css/petitions-grid.css -> modules/custom/petitions_homepage/css/petitions-grid.css
 	renamed:    themes/petitions44/js/homepage.js -> modules/custom/petitions_homepage/js/homepage.js

  Note: In addition to /homepage re-work, this also includes some updates to preproccessors. forward.tpl.php variables
  are now preprocessed here too...
 	modified:   themes/petitions44/template.php

Remove /homepage functionality from legacy wh_petition_tool module:
 	deleted:    modules/custom/wh_petition_tool/wh-petition-tool-homepage.tpl.php
 	modified:   modules/custom/wh_petition_tool/wh_petition_tool.module

Enable petitions_homepage module on update:
 	modified:   modules/custom/petitions_maintenance/petitions_maintenance.install

Enable petitions_homepage on fresh install:
 	modified:   petition.info
Update petitions44. Add documentation where missing. Tidy up some PHP.

This is mostly just documentation. In a few places logic is moved out of
.tpl.php files and into template.php (see previous commit). We also
tidied up some render arrays.

 	modified:   themes/petitions44/templates/block.tpl.php
 	modified:   themes/petitions44/templates/forward.tpl.php
 	modified:   themes/petitions44/templates/node--wh_petitions_page.tpl.php
 	modified:   themes/petitions44/templates/node--wh_response.tpl.php
 	modified:   themes/petitions44/templates/page.tpl.php
Update make filed for 7.x-1.0-alpha22 release.
Merge git://github.com/WhiteHouse/petition into 7.x-1.x