Jenkins build

The SDKLauncher-OSX had a build.xml to be used with jenkins, this pull request adds one for SDKLauncher-iOS that is almost the exact same (minus a few differences to account for the differences in the xcode projects between the two).

* allow building from the command line via build.xml
* add links to build status in the README

An example of the build status can be seen [here](https://github.com/datalogics-bhaugen/SDKLauncher-iOS/blob/jenkins-build/README.md). Don't be surprised that the status is failing, the build machine thinks that user interaction is required before it can sign an app, I am working on fixing that.