LLViewerWindow::handleKey(): Also handle keys for navigating through the displayed menu
LLViewerWindow::handleKey(): Partial Fix for Issue 704: Keyboard shortcuts that should be passed to focused text fields are instead passed to selected prims when building

All edit keys now work, but Ctrl-A still doesn't work right, it must be grabbed by something else...
Adds LLFocusMgr::keyboardFocusHasAccelerators()
Adds virtual bool LLView::hasAccelerators() which returns false by default, overrides returning true placed in LLPreviewScript and LLPreviewNotecard
Shortcut keys added to notecard and script menu xmls

I'm thinking Qarl's Align tool handling may be receiving the Ctrl-A, we do seem to handle it differently than Exodus and Firestorm something modern could have broken the old way..
Come to think of it, those two features(Align and Select all prims) have a longstanding shortcut conflict in shortcuts... that's pretty nasty
Sometimes UI get this syncing feeling... but then everything seems fine.