Added missing blz dependency in requirements.txt
Reform execution pipeline a bit (work towards better integration of new backends)
Assemble kernels into uniform python kernels
Adding unittest2 as a requisite for running the tests in Jenkins
Adding pip to the list of conda packages so that it can install unitttest2 in the correct conda environment.
Add return code checks of 'git clone' in jenkins build scripts
Remove obsolete execution context
Merge pull request #119 from markflorisson88/execution

Reform execution pipeline a bit (work towards better integration of new backends