(frontend) Add Xtext generator API
(frontend) Configure default ouput directory in OrccUtil
(frontend) By default, generator build IR file in 'bin' folder
(util) Add method to compute IR uri from CAL uri
(frontend) Implement basic generator
(refactoring) Change methods order in ActorTransformer
(frontend) Fix name of untagged actions in IR files

Now only 1 ActorTransformer is created for all builds
(frontend) Do not perform serialization in Transformers
(frontend) Stop using ActorBuilder
(frontend) Simplify Frontend methods

getMapping(EObject) has been removed.
Calls to the removed methods have been replaced by the equivalent
getMapping(EObject, true)
(frontend) Remove another useless method
(frontend) Comment useless code (consequence of 1c8da90bf321)
(frontend) Reduce usage of Frontend.getMapping() in UnitTransformer

This causes issues with forward declaration. Will be fixed later
(frontend) Reduce usage of Frontend.getMapping() in ActorTransformer

This causes issues with forward declaration. Will be fixed later
(frontend) Fix issues introduced in 9e6e4b and 45745d

Both Actor and Units declares their functions / procedures before
transforming it. This allows to use a function / procedure somewhere
before it has been declared (forward declaration)
(frontend) Add a warning in putMapping()

The method should not be used with an ast object
not contained in a resource
(frontend) Add a CalBuilder to use callbacks at start and end of a build
(frontend) Fix issues with references accross files

Issue: If an Actor in RVC imports a Unit in System, this Unit
is built under the RVC/bin folder
(frontend) Set name / type for each pre-declared procedure

If a call to a function / procedure returns something, and if this value
has to be stored in a temp variable, the created variable is named
from the called procedure name
(frontend) Remove problematic AstIrUtil.getLocalByName()

Fix #86