MXGDA-1376 use new braches for 8.40 development work
BUILD: allow more tailoring of Jenkins build jobs
BUILD: allow yet more tailoring of Jenkins build jobs
Use type rather than which for determining the buckminster install,
since it handles the case when "buckminster" is not an executable file
Better form of test
Revert "Use type rather than which for determining the buckminster install, since it handles the case when "buckminster" is not an executable file"

This reverts commit 5f14782d402d575517379845b7ebf6a82bd2db67.
Buckminster update for new plugin uk.ac.gda.component.samplehandling
(was previously applied to master, now to 8.40 and 8.42)
MX Now uses ispyb