Remove STATE_FOCUSED and STATE_SELECTED as requirements for focus mode

When using structural navigation, the grabFocus() we did might not be
sufficient to trigger a state-change.
Speak text role for Gecko apps when not in document content
Don't switch to focus mode if the object is a text block element
Do not present tutorial messages if the object is not the locusOfFocus
Prevent repeating of labels and tutorial messages in entries
Suppress tutorial messages for focus mode widgets when not in focus mode
Create new tutorial message for activating browse mode
Only use focused format type for objects which are not text block elements
Generate the rolename for links even if they were not "just entered"
Check for both focusable and focused states when determining text block elements

Some widgets, such as the Dojo combo box list, lack state focusable even
when focused. This check is a safe-enough workaround.
Remove the old, sad hacks from the Gecko script's findPreviousObject()
More hack removal and reworking of find{Next,Previous}Object()
Updated tests