Enhance project specific parameters example.

It was not clear that the project-specific parameters are actually a variables.
Improving the example to make it more clear.

Change-Id: I919562d4df53542ff0d4d60cf0fafc81b69aff1a
Added clone-workspace publisher

Change-Id: I39c71d69b100206e09164f0b765bda14d6f428c6
Fix misspellings in jenkins-job-builder

Fix misspellings detected by:
* pip install misspellings
* git ls-files | grep -v locale | misspellings -f -

Change-Id: I2443a0a3ae909457ee4f31a6837b445be03de0dc
Closes-Bug: #1257295
Merge "Added clone-workspace publisher"
Merge "Enhance project specific parameters example."