Add a method to test the existence of a signal.

Remove test for deprecated function

Reduce the memory consumption in the interpreter.

The goal is to reduce the memory consumption.

forced cmake to consider the 2.* versions of python first

  isPluged -> isPlugged.

[skip ci]

  - add isPlugged and getPlugged methods,
  - add property getter name.

pointed out by OS.

This is crucial when debugging remotely using winpdb.

Make possible to read the output from the process lauching the process.

Synchronize submodule cmake

This corrects the issue detailed here:
https://github.com/jrl-umi3218/dynamic-graph-python/issues/2

Solution found by Florent Lamiraux.

Pointed out by A. Mallet.