Update Rich Text Editor 3247, 3260, 3291, 3554, 3781, 3849 

- 3260 Rich Text Editor (RTE) needs double justify and right justify buttons http://code.google.com/p/otwarchive/issues/detail?id=3260

- 3291 Rich Text Editor (RTE) creates broken links to works on the Archive http://code.google.com/p/otwarchive/issues/detail?id=3291

- 3781 Instructions don't toggle when switching between RTE and HTML editor
http://code.google.com/p/otwarchive/issues/detail?id=3781

- Browser spell check doesn't work in RTE (no issue, just something I noticed was broken)

It also sort of fixes:
- 3554 RTE Align Left button does not work, creating code that is stripped by the parser http://code.google.com/p/otwarchive/issues/detail?id=3554

However, if you use the center tag in the HTML editor and switch to the RTE, you cannot use the alignment buttons to remove it. This is because I told the RTE to use the align attribute, which means it will not affect the center tag. So use align="center" instead of the center tag if you plan on switching from the HTML editor to the RTE for the purpose of using its alignment options. (It's probably not entirely unfixable, but I haven't gotten quite that invested.)

It may fix but I cannot test:
- 3247 Centre button in RTE does nothing in Safari 5.0.4
http://code.google.com/p/otwarchive/issues/detail?id=3247

- 3253 Anomalies pasting some types of formatting from Word into the RTE 
http://code.google.com/p/otwarchive/issues/detail?id=3253

- 3257 Rich Text Editor not recognizing formatting on text from Windows RTF editors
http://code.google.com/p/otwarchive/issues/detail?id=3257

- 3267 Rich Text Editor (RTE) stripping formatting when pasting with certain combinations of browser, operating system, and word processor
http://code.google.com/p/otwarchive/issues/detail?id=3267

This also adds a button for video embeds, as discussed in the AD&T e-mail thread "Update RTE?" from 11 August 2013. If you look at the [example editor on the TinyMCE site](http://www.tinymce.com/tryit/full.php), there are two tabs in the Insert/Edit Video popup. The General tab is geared toward uploads, which isn't something we offer. The Embed tab is where you paste the embed code just like you'd paste it into our HTML/plain text editor. Naturally, there's not a way to configure TinyMCE to only use the Embed tab on the Media plugin.

One more thing: there is no longer a special Paste from Word button, since pasting from Word is identical to pasting from everywhere else (this is true in our current version as well, but the button is still there). If wanted, I can add a plain Paste button (there are also Copy and Cut buttons) so we don't rely on users knowing the keyboard shortcut for pasting.

**Note: This pull request updates to TinyMCE 4.0.11. I'm sure I'll need to update again before we merge this, so I have not rebased and this is currently not able to be merged. Holler when we're ready and I will update TinyMCE again and rebase this.** This is rather isolated, so it shouldn't take more than an hour or two.