Improve script dependency declarations.

The JS for attachments and edit-validation are both dependent on the main
bp-docs-js script, but hadn't been declared as such in wp_enqueue_scripts().
This caused problems in some enviroments where certain script concatenation
was causing the scripts to be improperly reordered.
Readme
Bump version numbers to 1.8.x.
Merge branch '1.8.x'