Fix typos on SEO settings page
Fixed permalink bugs when the Permalink settings is set to Default.

Closes gh-221
Improve language loading to allow for custom paths.

Closes gh-233
Remove PO files.
Allow constants to be overridden.

gh-228
Add new contants to the Dashboard System widget.

gh-228
Update folder not exist/writable notices.

Closes gh-228
Fix double-slashing when registering template assets.
Purge cn_legacy_templates transient.

Closes gh-241
Remove double slashing that was occurring when registering legacy templates.
Fix malformed html in no template found error message.
Check template path exists before passing a template object; return FALSE.
Use ralative path when loading images via TimThumb.

Closes gh-176
Check that legacy template paths exist before returning the cached template object for said template.
Permit menu position to be set.

Setting CN_ADMIN_MENU_POSITION in wp-config.php will allow user to set
the position of the admin menu.

Closes gh-255
"Add to address book" link will no longer show on the default templates if not on in the settings.

Closes gh-231
Structure core class as a singleton.
Add action to cnUser constructor to set the current user ID var.
Add cnAdminFunction class.

gh-192
Add cnAdminMenu class.

Closes gh-192