(backends) Remove ref to doVtlCodeGeneration() when not needed
(backends) Clean backends options, add documentation
(backends) Ensure 'options' map is not visible

Also rename getAttribute() methods -> getOption()
Concrete backends must use getOptions() instead of the variable
Fix mispelling error
(RenameTransfo) Remove useless constructor signature
(Jade) Fix Validation error with Mpeg4 Part10 PHP

PHP design contains actors with ports named "SELECT". "SELECT" is in
replacement Map, so these ports are renamed "select_". Since now actors
and network are unserialized with the same ResourceSet, the rename
transformation must be applied on network and actors after all these objects
have been unserialized.
Merge branch 'master' into backends_refactoring
(backends) New method to allow back-end execution cancellation
(backends) Replace compileVTL() and compileXDF() calls by their content
(Jade) Remove one more useless method

VTL specific backends methods have been deprecated.
New method to apply transformations from common maps have been added
Note: Jade backend still works at this point
(transformations) Set DfVisitor as base class for 2 transfos

Instantiator and NetworkFlattener
(jade) Apply transformations from the common maps
(llvm) Allows empty constructors

Options map should now be passed with setOptions() method. This will
allow to have only 1 InstancePrinter instance for all generated files

Note: Old constructors new(Map<String, Object> options) can't be set
to Deprecated since it causes NullPointerException, popup messages and
highlighting issues in Xtend editor
(jade) Use the new way to print actors

Only 1 ActorPrinter is created in the backend
(jade) Minor improvements

Disallow usage of ActorPrinter with an Instance
Correctly call super methods (setActor())
Add traces
(jade) Remove useless methods definition and calls
(backends) Remove useless isCanceled() method

Re-enable monitoring of backend execution
(jade) Now fully migrated to new backends workflow
(core) Implements toString() method in Result class
(backends) doVtlCodeGeneration method is now completely uiseless

It has been removed