Check if file exists before opening OPI

This prevent an issue where an OPIView opens
even when the OPI file doesn't exist. It also
prevents mutiple exceptions occuring in this
case.
Merge branch 'css-60'
Added scripts to update pom and manifest versions
Removed some plugins from the build
Commented out some plugins from o.c.core.all.feature
Updated version on all core plugins
Merge branch 'tycho-fixes'
Added initial draft of DLS product
Removed unneccassary plugin customization
Updated plugin_customization to Diamonds previous one
Added databrowser to feature list and loads of plugins
Added remote target
Dummy diamond paths are the default in preferences.

This in in preference to non-working paths from NSLS2,
however these should be changed to a more suitable
configuration when a Diamond one exists.
Add color.def for Diamond.
Added CA-Gateway to CA Address list

For some reason this is required to see
PVs through the gateway after a tycho build,
but not when running a from the IDE.
Unpack product plugin to dir instead of jar
Added font.def and also added color.def to build output
Modified font file to provide same options as EDM
Merge branch 'dls-product'