Add esc_textarea() to functions.formatting.php.
SQL Parser: don't issue notices if a field doesn't have length

The code tried to access a non-existing index and this generated a
notice, even though the code worked fine.
Formatting: Update the formatting functions to match [WP20951]


Highlights:
 * Updates make_clickable to be more performant and support more types of urls including better support for parentheses.
 * Updates sanitisation functions to support context and perform different levels of sanitisation for db and display.

Updated functions:
 * wptexturize, _wp_specialchars, remove_accents, sanitize_user, sanitize_title, sanitize_title_with_dashes, force_balance_tags, format_to_edit, stripslashes_deep, make_clickable, is_email, ent2ncr, esc_url, like_escape

New functions:
 * sanitize_key, rawurlencode_deep, wp_basename, sanitize_mime_type

See #24
merge in helper __return_* functions from WordPress core, see #31
Create bbpress 1.2 branch.

* Fixes pomo external issues.
Delete conflicting pomo directory in bbPress 1.2 branch.