o.c.opibuilder.widgets.edm: Fixed potential bug in symbol widget

If two symbol files have the same name, and are references by the same
relative path, then they would have identical keys in the cache. By using
an absoloute path this is avoided.
Merge branch 'edm-symbol-widget' into dls-product
DLS Product: Added csstudio target
Merge branch 'target-fixes' into dls-product
Corrections to dependencies for DLS plugins.

Necessary after reexports were removed.
DLS product: large default value for max_array_bytes
DLS Product: Added opibuilder 4.0.102 to list of required plugins
EDM Converter: Use special close method that works with OPI Shells
Added dedicated method for closing OPIShells

Existing code to close the parent shell was unreliable. This method
requires the assocaited widget to be passed in, so its can provide
a handle to the shell being closed.
Edm Mode: Fixed bug in OPIShell resizing
Merge remote branch 'remotes/dls-github/converter'
Merge remote branch 'remotes/dls-github/converter-edm'
Merge remote branch 'remotes/dls-github/edm_clean'
Merge remote branch 'remotes/dls-github/dls-product'
Merge remote branch 'remotes/dls-github/std_dev_clean'
Merge remote branch 'remotes/dls-github/build-hacks'