Do not include external URLs in XML sitemap (Issue #528)
Fix XML sitemapsDo not include external URLs in XML sitemap (Issue #528) - updated according to jdevalk's comments
Get home_url out of the loop
Merge pull request #588 from tivnet/master

Do not include external URLs in XML sitemap. Fixes issue #528. Props @tivnet
Added props to readme file
WPSEO_FILE & WPSEO_VERSION now have a defined check
Refactored the WPSEO_Options class, now split in three components

- an abstract WPSEO_Option class as a master for each option
- a concrete WPSEO_option_{option_shortname} class for each option implementing the abstract class
- a separate WPSEO_Options class which handles instantiating the option classes, access to them and multi-option functionality

Also:
= Admin pages =
* Removed most hidden fields from the admin pages while still retaining their values between saves
* Fixed: Some headers could/would be shown on admin pages, even if there was no content for that header
* Moved the bold-last breadcrumb tickbox up for a more logical placement on the page
* Fixed: bug in import from WooThemes SEO
* Fixed: bug in export where boolean values wouldn't import correctly anymore
* Added some extra error messages were I deemed it necessary
* Fixed: bug where message about files blocking the sitemap from working would not be removed when it should.

= Admin classes =
* Changed the upgrade logic completely, including the setting of defaults on activation and such. This should also have a positive effect on must-use installations and multi-site installations.
* Made it so the export functionality can deal with boolean values
* Moved some functions around:
	- WPSEO_Admin::grant_access() -> WPSEO_Options::grant_access()
	- WPSEO_Admin::maybe_upgrade() -> inc/functions.php wpseo_do_upgrade() and most of the logic to the clean_option() methods
	- WPSEO_Admin_Pages::reset_defaults() -> WPSEO_Options::reset()
* Added running of title_test() on upgrade/switch theme

= Front end classes =
* Now only loads breadcrumb file if the template tag is encountered
* Fixed bug in breadcrumbs where an empty element would result in two separators after each other
* Fixed some over enthousiastic escaping of the text strings in the breadcrumbs class
* Fixed mini-bug in breadcrumbs in the output logic (link tag even when no link)

= Various =
* Removed some back-wards compatibility for WP < 3.5
* Made several tweaks in functions/methods to make them more efficient
* Better deprecated messages
* Added yet some more @todo's and clarified some others (oh, removed quite a few too ;-) )
* Added yet more {} around one-liners
Merge remote-tracking branch 'jdevalk/master' into Fix-settings-issues

Conflicts:
	inc/class-sitemaps.php
	readme.txt
	wp-seo.php
Removed already addressed todo
Merge remote-tracking branch 'jrfnl-fork/Fix-settings-issues'