nitx: no more refinement of to_s methods

Signed-off-by: Alexandre Terrasa <alexandre@moz-code.org>
nitx: is now able to look for generic types

ex:
"Array" # return class doc for Array
"Array[String]" # return doc for class Array
"return: Array" # return doc for mmethods returning the static type Array
"return: Array[String]" # return only doc for mmethods returning the static type Array[String]

Signed-off-by: Alexandre Terrasa <alexandre@moz-code.org>
nitx: added lookup for instance creation.

'new: Type' return the doc of methods creating new instances of Type

Signed-off-by: Alexandre Terrasa <alexandre@moz-code.org>
nitx: rethinked architecture for further developments


Signed-off-by: Alexandre Terrasa <alexandre@moz-code.org>
Merge remote-tracking branch 'alexandre/nitx'

Conflicts:
	src/nitx.nit
nitx: nitx_phase is private, because NitxPhase is private

Signed-off-by: Jean Privat <jean@pryen.org>
nitx: do not crash if nmodule.n_moduledecl is null

Signed-off-by: Jean Privat <jean@pryen.org>
tests: update nitx

Signed-off-by: Jean Privat <jean@pryen.org>