Merged in viewer 2 changes, adjusted xui problems, added mesh folder type and more mesh inventory type info

EXT-1503 Cosmetic and Polish issues with Viewer 2.0 Internal Alphan -- Notifications with long headlines are overlapping with text

http://jira.secondlife.com/browse/EXT-2312

Notifications console was listed twice in the Develop>Console menu

Develop>XUI>Send Test IMs: Lets not poke fun of a resident tradition in the public beta. Also it should test a sentence that wraps. Ideally it would also test a string with double-byte characters but I dont know how to do that.

The active parcel media instance always gets priority over other inworld media.

PARTIAL FIX (workaround) DEV-41949: LLMediaEntry::setWhitelist() and LLMediaEntry::asLLSD() have a contract conflict
Review #31

So, here's what was happening, briefly:

- LLMediaEntry::setWhitelist() would be a no-op if given an LLSD that did not have a WHITELIST_KEY
- LLMediaEntry::asLLSD() would render the LLMediaEntry *without* a WHITELIST_KEY if the whitelist was empty

Therefore, when the viewer marshalled an LLMediaEntry for the server, it would send it without a WHITELIST_KEY. When the server got it, it would not erase the last value.

This is actually a workaround: it patches asLLSD() with an LLSD::emptyArray() if the key is not there. However, this should be fixed on the server: in either or both of the following ways:

1) LLMediaEntry::setWhitelist() should not be a no-op if the LLSD has no WHITELIST_KEY: it should erase the whitelist
2) LLMediaEntry::asLLSD() should render an empty whitelist in WHITELIST_KEY as an empty array

Note that both could be done and still work.

A unit test should and will be written next.

Created LLViewerMediaImpl::unload(), which unloads the media and clears internal state (such as the last-navigated URL) to keep it from getting reloaded.

LLViewerMedia::updateMediaImpl() now calls unload() on the impl instead of just using destroyMediaSource().

This change gets rid of the crufty (and confusing) "apply()"
functions from llpanelmediasettings*.  Those functions were
never being called, yet changes were being made in them.

Instead, I added "preApply()" and "postApply()" to each of
these panels, which the floater (who really does the "apply()"ing)
now calls before and after it applies the changes to the
media data.

Made LLViewerMedia::updateMediaImpl() unload the impl's media plugin when the current URL goes empty.

Made LLVOVolume::syncMediaData() call removeMediaImpl() if the media data gets deleted.

The various People panels now have Call buttons that work. Currently
we only support single selection of users in lists for P2P voice chat.
Multiple selection for ad-hoc chat is next...

converted mWorldViewPlaceholder to a LLHandle<LLView>
improved layout of panel_bottomtray

reviewed by James

Sending now works.
Reviewed with Ambroff.

Disabled saving notifications to disk because the load code hasn't worked for months, it spams the logs, and it hits the disk.
Discussed with Q, the author.

Reviewed with Ambroff

EXT-1219 Side tray slide-out animation
cleaned up some layout of bottom tray contents

reviewed by James