YAMPL Patch Fix, master branch (2020.10.01.)

Added a forcedownload build step to yampl. This should allow us to update how it would be patched, a bit more robustly in the future. Unfortunately the previous update, which was included into atlas/athena with athena!36719 (merged), caused some harm in the incremental builds of the CI system. 😦

At the same time I added some quotes around directory name variables. To make it a bit more feasible to do builds in directories with spaces in their names in the future. (Unfortunately the yampl configure script can not receive the installation prefix in quotes though...)