Support import of partial configuration

[GoogleCodeExporter]

Extend import capability to allow merging partial config data into the
existing configuration.  When a project name or scheduler name is
duplicated, rename the project by adding "imported" or something to the name.

Options for conflict resolution:

When a project requires a plugin that is not present, either set the plugin
config to null or reject the import.

When plugin config data is present check to see if the data is equal to the
existing configuration.  If not, either:

o Reject the import
o Ignore the conflicting imported data
o Overwrite the existing data with the imported data

Original issue reported on code.google.com by [email protected] on 22 Oct 2006 at 6:19