Added new options to ClangFormat VSIX package.

Summary:
Added new options to ClangFormat VSIX package:
* fallback-style
* assume-filename
* sort-includes.
Changed version to 1.1 (otherwise one couldn't update).

Fixed clang-format escaping of XML reserved characters.

Reviewers: hans, aaron.ballman, klimek, rnk, zturner

Subscribers: djasper, cfe-commits

Differential Revision: http://reviews.llvm.org/D13549

llvm-svn: 250694