Don't use seekable if metadata isn't loaded.

Using seekable before then observed to cause several devices to hang when playing HLS
Merge branch 'master' into new-media-api-seekable-fix

Conflicts:
	static/script-tests/tests/devices/mediaplayer/html5commontests.js
Fixed failing test to use new getSeekableRange function
Merge pull request #196 from fmtvp/new-media-api-seekable-fix

Don't use seekable if metadata isn't loaded.