Use swap_node instead of add_node when replacing conductors.

change on_punch to on_rightclick, make disabled blinky plants drop norma...

here and there to facilitate this.

Make blinkyplants toggleable

LGPLv3 for code,
CC-BY-SA-3.0 for everything else
This should makes it easier for packagers of distributions

Permitted according to section 4b of CC-BY-SA-2.0:
"a later version of this License with the same License Elements as this License"

Give crossing proper textures

Multi rules
Merged for near-future textures to be merged cleanly.

Fixes https://github.com/Jeija/minetest-mod-mesecons/issues/108

Support cyclic references in luacontroller memory tables, prohibit usage of goto statement (bugs reported by Nore).

Change mesecons signals so that they update effectors only after a globalstep, configurable to be on/off

Add an ABM function which resets heat to 0, ...

Add an ABM function which resets heat to 0, since gates/controllers won't be cooled normally if they are moved (piston, etc...) during the cooling delay.