WP_filesystem changes to work with new directory constants

[DD32]

Thanks to #6938 and [7999] the WP Filesystem abstraction classes need a update in order for the plugin upgrader to continue working.

• All Fielsystem classes now extend the WP_Filesystem_Base class
• The code now has a few methods to get the various folders needed: wp_content_dir(), wp_plugins_dir(), abspath(), wp_themes_dir()
• The find_folder() method should locate any real path on the server hopefully. Be warned there will be cases where it'll locate the wrong folder if the requested folder doesnt exist.
• The gethchmod() and getnumchmodfromh() methods which were common have been moved to the base calss
• The upgrader code has a few extra error cases builtin (Eg. Copy Failed messages will now indicate what copy process failed)
• A lot of whitespace additions to the classes

Warning: Tested in a few setups, Needs a full testing with a variety of custom setups.

oops, a extra function sliped in :)

(In [8009]) Make WP_Filesystem work with new directory constants. Props DD32. fixes #7059

(In [8010]) Typo fixes from azaozz. see #7059

(In [8009]) Make WP_Filesystem work with new directory constants. Props DD32. fixes #7059

The patch included an extra file wp-admin/includes/class-wp-filesystem-base.php which wasnt commited.

Thanks for the catch on the typo's Azaozz, I really need a spellcheck plugin for Dreamweaver that understands literal strings..

attachment 7059.3.diff added.

• The Base class
• Corrections to the ftpsockets class.

Corrections to the ftpsockets class.

Note: That this is not the same as the one in the original patch.

(In [8018]) WP_Filesystem updates from DD32. See #7059

get_page_templates() was breaking for me, attached patch fixed it.

(In [8051]) Use WP_CONTENT_DIR in get_page_templates(). Props ionfish. see #7059