js: Only autodetect utf-8 if Content-Type does not specify charset
Make it possible to build without webkit
Update some build instructions
js: Repair broken UTF-8 before passing it to Spidermonkey
glw: Make (cancel) work in Showtime's own OSK
js: Fix possible crash in pb_getProperty
Fix bug causing action to be invoked when menu item was destroyed.

Resulted in a bunch of weird things such as marking all items seen
when leaving a directory, etc