Revert "Revert "I had recently added a new SBFrame::GetVariables() overload...

Revert "Revert "I had recently added a new SBFrame::GetVariables() overload with yet another bool argument""

Reverting this commit led to other failures which I did not see at
first.  This turned out to be an easy problem to fix, so I added
SBVariablesOptions.cpp to the CMakeLists.txt.  In the future please
try to make sure new files are added to CMake.

llvm-svn: 229516