Initial commit (Output of the Xtext wizard)
Grammar "with XbaseWithAnnotations"; add "(annotations += XAnnotation)*"

- Extend the grammar from
org.eclipse.xtext.xbase.annotations.XbaseWithAnnotations
- Add annotation support for operations
- Rerun the workflow generator
Inferrer: generate op-annotations & interface, test it

- Generate specified annotations on operations
- Generate a simple interface with methods (derived from operations)
- Fix CompilerTests (revealing actual problem)

PS

Making interface methods associate with entity rather than
with f (Operation) fixes the NullPointerException but messes up the
navigation later on making users of my plug-in mad!