Update .arcconfig to point to reviews.llvm.org

Mostly a test review and commit.

Reviewers: tfiala

Differential Revision: http://reviews.llvm.org/D3834
Move the function and data section flags into the options struct and
make the functions to set them non-static.
Move and rename the llvm specific backend options to avoid conflicting
with the clang option.

Paired with a backend commit to update.