Added an option to allow short function bodies be placed on a single line.

Summary:
The AllowShortFunctionsOnASingleLine option now controls short function
body placement on a single line independent of the BreakBeforeBraces option.
Updated tests using BreakBeforeBraces other than BS_Attach.

Addresses http://llvm.org/PR17888

Reviewers: klimek, djasper

Reviewed By: klimek

CC: cfe-commits, klimek

Differential Revision: http://llvm-reviews.chandlerc.com/D2230