fundraiser view nitpicks, take two

Fixes #57.

- [x] Show updates/titles above the fundraiser body (like we did in previous frontend)
- [x] italicize the “# claimed” text (or use something bootstrapy) to differentiate the text
- [x] Rename Pledges tab and URL to “Backers”
- [x] “By developername” text is lost on all subpages, let’s bring it back ***(was already fixed)***
- [ ] Facebook share button needs to come back
- [x] Change default wording on Twitter/Facebook shares “Support (fundraiser name) on @Bountysource! urlhere”
- [x] URLs for home and repo are missing ***(was already fixed)***
- [x] if you're the creator, and the fundraiser has ended, add an alert to the top "All money raised is now in your Bountysource account. You can request a cash out here."
- [x] pledge now screen... change reward Reward Survey title to “Reward Survey. You can edit your response later if you need to.”

Twitter was not interpolating the variables reliably (sometimes it worked, sometimes it didn't) - I couldn't trace it down but I suspect it has something to do with the async / intervaled nature in which the Twitter library is loaded, not sure. Another possible cause might be these two errors I noticed on the console (again, only sometimes):

    Uncaught TypeError: Cannot call method 'apply' of undefined services.js:88
    Uncaught TypeError: Cannot call method 'apply' of undefined services.js:133

Because of this, I ended up implementing the tweet button with an `iframe`.
And to make the URL interpolation reliable, I also had to implement a `encodeURIComponent` filter.