* New MV hydro with upgraded power
The LV hydro is easy to make giving lot of power. The New hydro MV will put a tier system to it; thereby giving more incentive to player to pursue MV hydro plus a little survival aspect. This is a result of [Detailed discussion which is here](https://github.com/minetest-mods/technic/issues/411). Thanks to VanessaE for a good talk and support and enthusiasm to make one :) This will now produce around 175 EU (in between 150-200, so basically average). The MV hydro will give 10x more power than this one. :)
Add the EU_string helper function
In comparison to pretty_num it uses SI prefixes, adds "EU" (e.g. kEU) and rounds the number for readability
Add a constant_digit_count boolean setting
delete back/bottom texture for power monitor
use "machine bottom" for bottom of force field generator
add cable connection overlay, use it on various machines' bottoms/sides, as appropriate
Water flow around a gen is shown more or less directly by the water's
param2, range 0 to 15, so four sides could total 60. Cap the result to 45
so that three sides' worth of full flow (or four sides at reduced flow) still
registers as "100%", and raise the maximum outpu to 2250 EU.
Changes:
* Make rayIter a global utility, and use it for radiation too.
* prettynum -> pretty_num and cleanup.
* Remove resolve_name/function_exists (unused).
* Cleanup nuclear reactor code.
Note: this required renaming the base node name for the oblate spheroid
object, which previously had been named simply "sphere". The result is
that all such nodes in an old world will change to actual spheres.
Since this includes a formspec change, machines will have to be dug and
re-placed to get the new program button to show up, and/or if the image
on the Oblate Spheroid button shows wrongly.
If an operating music player was disconnected from the electrical network
or destroyed, it used to leave the music playing forever. There was
also a glitch upon starting playing, as the music was started by the
form handler but then stopped when the run function realised it wasn't
receiving any power, because it hadn't demanded any yet.
LV cables are now paper-insulated, rather than uninsulated (which made
no sense). MV cables are rubber-insulated as before. HV cables are now
plastic-insulated (which they already visually appeared to be). MV and
HV cables are still crafted by adding insulation onto lower-tier cable,
rather than by insulating raw copper; this matches the way machines are
upgraded between tiers rather than crafted afresh.
All electric machine recipes now include cable of the appropriate tier
as the bottom-middle ingredient, immediately below the casing ingredient.
Many LV machines were using a copper ingot in that location.
