Nightly builds, next step

this is the next step you might want to have a look at.

add dependencies and build scripts to be able to build all configurations from the solution SparkleShare.sln

the used git binaries are now included (as git.tar.gz) and will be extracted during build from the archive

build configurations are now:

* Debug: with debug symbols and symbol DEBUG defined
* Release: without debug symbols, with optimizations, depends on installed Mono framework
* ReleaseDist: like Release, but all depending frameworks are merged into one OSX binary, installed Mono framework not needed / used

The automated build on this only needs a normal jenkins installation, that executes the very same solution like from Xamarin and packages it.
This is the automated output for the ReleaseDist config:

https://www2.junidas.de/download/SparkleShare-nightly.tgz