startuphelper: moving startuphelper from CS_STUDIO to core

Change-Id: I3bd30b08638803476d347d4c22d32d638f49cc9b
NSLS2: replacing nsls2.startuphelper with the common one

Change-Id: Icbae412bceab5b0482dd68f79bd4c0cb17f010d4
product: creating a common product helper, removing all the source code
from the nsls2 product and replacing it with a dependency to
product.helper
Site specific contributions can be made using the plugin_customization
and messages.properties included in a fragment

Change-Id: I53919798425c1fe664b48944a0b78251fe7c7d50
NSLS2: fixing the plugin.list using the compute dependency

Change-Id: I8faddc250a5cf27bf337abb3d18ba5e7641276c5
..product.helper: fixing classpath settings 

Change-Id: Id457dbe66347907e966f00847923fb6047b11934
Merge branch '3.2.x' of ssh://git@github.com/ControlSystemStudio/cs-studio.git into 3.2.x