Document source_encoding setting.

Fix a few others after digging into the config module source.
Add compatibility for clang 3.5 (svn)
- FunctionDecl::getResultType() was renamed to FunctionDecl::getCallResultType()
- We were misusing DiagnosticsEngine::getCustomDiagID as it should always
  take a constant string.  Switch to using formatted output to make this work
  on both clang 3.5 and previous versions.
- Correct a copy-paste error where we were printing the name of the output
  directory instead of the name of the temporary directory in an error
  message.
Merge pull request #290 from abbeyj/clang-3.5

Add compatibility for clang 3.5 (svn)
I don't like how that Sphinx theme looks on readthedocs. Let's take advantage of the pretty readthedocs default theme.
Correct docs: dxr-build is the indexer, not dxr-serve.
Changed protocol for trilite submodule
Change folder name that was causing git checkout to fail on Windows.
Restore the missing "bubble" element which somehow got lost. Fixes bug #1039644.
Pull contributors toward the Development page.

I forgot myself that Getting Started wasn't target at developers. Whoops. We should make that even clearer at some point.
Make search results more scannable. Fix bug 968017. Close #304.

Also clean up a lot of the CSS.

Increment format version, since we changed a lot of markup, and the new CSS probably won't work well with the old.
Merge master into es to get the folder.html and other changes.