touch -c instead of touch --no-create for mac compatibility
Build against any R for OSX

The most important changes are:

 - use C++11 for ALL THE THINGS. This is the reason why boost > 1.54 was unhappy. ALL THE THINGS includes RInside, so we build it with

    R CMD install --configure-args="CFLAGS=--std=c++11" RInside<version>.tar.gz

 - Distinguish between R_FRAMEWORK and R_HOME for OS X

 - Boost usually installs to /usr/local/include (homebrew does that, for
   example), but that's not in the standard search path for how qmake calls
   clang++ (????). So we need to support passing a BOOST variable to the
   configure script. Default to ../boost_1_54_0 for compatibility with what
   the build documentation says.