Use function for span here

git-svn-id: http://textpattern.googlecode.com/svn/development/4.x@5341 2fea6a4d-a838-0410-917b-93a53c48e9d2
Moved TextpatternLoader to its own file.

Drops dependencies and allows calling the loader before
anything else. Renames the class to Textpattern_Loader
in the process.

git-svn-id: http://textpattern.googlecode.com/svn/development/4.x@5342 2fea6a4d-a838-0410-917b-93a53c48e9d2
PSR-0'd the new 'txp:if_yield' tag.

git-svn-id: http://textpattern.googlecode.com/svn/development/4.x@5343 2fea6a4d-a838-0410-917b-93a53c48e9d2
'txp:if_yield' compares values strictly as strings.

Avoids type juggling issues. This allows telling the
differences between numeric-like values or
'empty' bytes.

git-svn-id: http://textpattern.googlecode.com/svn/development/4.x@5344 2fea6a4d-a838-0410-917b-93a53c48e9d2
Should be get_pref().

git-svn-id: http://textpattern.googlecode.com/svn/development/4.x@5345 2fea6a4d-a838-0410-917b-93a53c48e9d2
Merge remote-tracking branch 'upstream/master'