This also enables the Screensaver target to test if it can be built on Travis now.
Note: I tried to refactor the duplicated code into a bash function but string and variable interpretation screwed up the arguments passed to BuildMacBOINC.sh and I couldn't get it to work.
Fixes some copy and paste bugs reported by Charlie Fenton.
Added ScreenSaver target aka screensaver coordinator which was missing from the CI build script.
This allows to build BOINC on a Mac CI system as well as on a developers computer. See script headers for documentation.
The short version is:
* run ./3rdParty/buildMacDependencies.sh to compile all dependency libraries into 3rdParty/buildCache/mac (can be configured with --cache_dir)
* run ./mac_build/buildMacBOINC-CI.sh to compile all BOINC components using the build cache (--cache_dir can be used here too)
There are options for building debug versions but they are not very well tested. Currently you can't selectively build single targets using this.