Issue #988954 by beejeebus, tim.plunkett, aaron: Create upgrade path from Embedded Media Field (6.x) to Media module (7.x)

#988954: first steps, hook in to content_migrate module, map emfield fields to media module, and clean out D6 code

* Simplify regex for image_ncck_flickr_extract, to eventually allow better photoset imports (a_c_m).

* Simplify regex for image_ncck_flickr_extract, to eventually allow better photoset imports (aaron).

#266524 - joachim alerted us to the fact that some of the links on settings pages and in the documentation pointed to the wrong place

add custom urls
add soundclick provider

#214011 - dgtlmoon fixed variable syntax that was precenting users from choosing which providers should show up and which shouldn't on the CCK form.
#261999 - chirale fixed XHTML validation errors in YouTube.inc