SWIG experiments

Squash of the following commits (a full rebase was too hard :( )
* ef309cfdf N - SWIG: create pm3.c (5 months ago)  <Philippe Teuwen>
* 05ba6a73f N - swig pm3_device -> pm3 (5 months ago)  <Philippe Teuwen>
* d59630183 N - swig: move pm3.i (5 months ago)  <Philippe Teuwen>
* 6adcfad75 N - Fix historic make & cmake (5 months ago)  <Philippe Teuwen>
* bcbef2edf N - Fix typo with script_embedded (5 months ago)  <slurdge>
* 538ee4dab N - Better SWIG integration: autogen func & attributes (5 months ago)  <slurdge>
* 756b62466 N - SWIG: few helper scripts (5 months ago)  <Philippe Teuwen>
* 47ba4acd0 N - SWIG %extend (5 months ago)  <Philippe Teuwen>
* 21841cb9d N - simplify scripts (5 months ago)  <Philippe Teuwen>
* 78c4f7929 N - Revert "SWIG experiments: introduce context" (5 months ago)  <Philippe Teuwen>
* 1562b75fc N - SWIG experiments: introduce context (5 months ago)  <Philippe Teuwen>
* a503dfcd9 N - SWIG experiments (5 months ago)  <Philippe Teuwen>

client/experimental_lib/example_lua/01link_lib.sh

@@ -0,0 +1,3 @@
+#!/bin/bash
+
+ln -fs ../build/libpm3rrg_rdv4.so pm3.so

client/experimental_lib/example_lua/02run_test.sh

@@ -0,0 +1,8 @@
+#!/bin/bash
+
+# pm3.so somewhere in default LUA_CPATH :
+# /usr/local/lib/lua/5.2/pm3.so
+# /usr/lib/lua/5.2/pm3.so
+# ./pm3.so
+
+./test.lua

client/experimental_lib/example_lua/test.lua

@@ -0,0 +1,6 @@
+#!/usr/bin/env lua
+
+local pm3 = require("pm3")
+p=pm3.pm3("/dev/ttyACM0")
+p:console("hw status")
+print(p.name)