[clang-tidy] Add check misc-braces-around-statements.

This check looks for if statements and loops: for, range-for, while and
do-while, and verifies that the inside statements are inside braces '{}'.
If not, proposes to add braces around them.

Example:

  if (condition)
    action();

becomes

  if (condition) {
    action();
  }

This check ought to be used with the -format option, so that the braces be
well-formatted.


Patch by Marek Kurdej!

http://reviews.llvm.org/D5395

llvm-svn: 218898