refactor bootstrap.sh (simplify external patching)
add externals/tbb for homebrew TBB
add TBB into build procedure
FIX: add libtbb*_cvmfs_*.so.2 to the installation procedures on linux
use the main tbb shared library file as sentinel for rebuild decision
rename CMake variable TBB_HOMEBREW to TBB_PRIVATE_LIB
add custom TBB shared objects to the rpm spec file
FIX: trailing space in rpm spec file
add addtional clearification of patch files in README
indentation of 'repackage script'
FIX: use CMake variable for shared lib extension
Merge pull request #209 from reneme/integrate_tbb

Integrate TBB external into Build Process

This adds Threading Building Blocks as an external to the build process of the cvmfs_swissknife binary.
Note: TBB cannot be linked statically and we therefore generate and install a (custom named) shared library.