Updating blog plugin for streams.

Now the blog plugin can take all of the parameters available to streams.

Closes #2406.
Sending any attributes to theme:partial will make them available in the view.
Merge branch '2.2/develop' of github.com:pyrocms/pyrocms into 2.2/develop
Merge pull request #2410 from donaldallen/2.2/fileUploadNon-mod_rewrite

Allows File module upload to work if site not using mod_rewrite
Fix in french blog lang file

The english slug is "read more" so the translation should be "Lire la suite".
This is more relevant and meaningful.
Merge pull request #2413 from tristanjahier/2.2/develop

Fix in french blog lang file
Fixed a bug in the installer where Step 4 could white screen with no errors output
Bug Fix: Only set validation rules on submit

The validation rules of the contact plugin were causing issues with
other forms on the same page.

This is easily prevented by setting the validation rules only when the
contact form is actually submitted.

The long list of additions and deletions is due to a change in
indentation, caused by splitting up one if statement into two if
statements on lines 259 and 263.

This simple fix is also included in
https://github.com/pyrocms/pyrocms/pull/2414, but I'd appreciate it if
this could already be part of 2.2.
Merge pull request #2415 from Solinx/2.2/Contact

Bug Fix: Only set validation rules on submit
Fixed a grammar error that showed when no streams existed
Added a check to the Themes admin so it doesn't error if a theme doesn't
return any options
Removed animation of folders and files to fix #2402
Updated the Image & File field types' message when no folders are available to select
Added missing Page Type description to new installs
Recursively mkdir cause site dir may be new too
Merge branch '2.2/develop' of github.com:pyrocms/pyrocms into 2.2/develop
Fixed some issues in the blog:posts plugin. #2418
Added .datepicker class

I added a class to the selector. In one view may be more than one datepicker.
Fix for overzealous where parser.

There process where function was adding table prefixes where it shouldn't have been. This is the fix.
Fix for categories in posts plugin.

Fixes #2418.