Introduce backpat functions for < BP 1.7.

This is so we can utilize BP's new template-loading approaches like the
template stack and use other functions like bp_get_template_part().
Reformat template loader.

Previously, BP Album would supply its own templates as a full template
(using get_header() / get_footer()) and not as a template part.

See:
/members/album/pictures.php
/members/album/single.php

Since BP 1.7 opens up BP to all themes, this doesn't work so well.

What we do in this commit is:

1. Allow themes that are already using these older templates to continue
   working as-is
2. Change BP Album to use /members/single/plugins.php as the template so we
   can inject templates into BP without changing the surrounding markup
3. Re-route older template locations to use our new templates to avoid
   conflicts.

   New templates reside in:
   /buddypress/members/single/album
Remove older templates bundled with BP Album.
Make sure bp_album_load_subtemplate() supports our newer templates.

Use bp_locate_template() to load templates instead of STYLESHEETPATH /
TEMPLATEPATH lookup.
Rename older template name to newer one.
Merge pull request #4 from r-a-y/theme-compat

Theme compatibility
Add action hooks for deleting pictures from album

A new bp_album_delete_picture action hook is called just after the picture files are deleted from disk.
Merge pull request #6 from oblaksoft/patch-1

Add action hooks for deleting pictures from album
Use load_plugin_textdomain() instead of load_textdomain()
Merge pull request #7 from BP-Media/textdomain

Use load_plugin_textdomain() instead of load_textdomain()
Add a new pot file for translators

Update .gitignore
Update French Translation
Merge pull request #8 from BP-Media/update-pot

Add a new pot file for translators
Update the French translation
Merge pull request #1 from BP-Media/master

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