Added it to .hgignore.
This gets rid of spurious differences caused by CMake regenerating it differently.
Just run 'cmake .' to get it back in your local checkout.
To build out-of-source, follow these steps:
# [[Insert LLVM build instructions here]]
mkdir my_build_dir
cd my_build_dir
svn co http://svn.dsource.org/projects/tango/trunk tango
ccmake <PATH_TO_SOURCE>
# (Regular ccmake stuff, press 'c' a few times followed by 'g')
make
make runtime
# add `PWD`/bin to PATH
closes#213
