* Apply #pragma once in headers
* Adjust some thermistors formatting
* Misc cleanup and formatting

Values taken from Zonestar firmware for P802QA with a Melzi board. Timestamps from the firmware package are from April 2016.

agData in Table 71 is extremely oversampled (see Issue #11220). I have removed the data points that perform *worse* than linearly interpolating the remaining points, and fixed up two points that were simply rounded incorrectly.

Co-Authored-By: Aaron Griffith <aargri@gmail.com>

Indeed the HAL does not need to be mucked around with to expose ATmega2560 pins not available as numbers on the MEGA board, I'll need to update the wiki with that tidbit and a reference to the pin-mapping comment in `fastio_1280.h`.

Co-Authored-By: Aaron Griffith <aargri@gmail.com>

* Allow both AD595 and AD8495 in concert
* General temperature code tweaks

This is an initial cut for feedback, updated for 2.0.x.

Chamber temperature is currently reported along with hot end and bed
temperatures to serial. The format is just like that used for hot end
and bed temperatures, but using 'C' prefix. As there is no heater,
target is always 0. Is this appropriate, is there a better way to report
chamber temperatures?

Chamber temperatures are not reported on the LCD in any way.

When auto chamber fan is enabled, it currently just uses the same
temperature threshold as the other auto controlled fans.

As the chamber temperature is not connected to any heater, it doesn't
undergo mintemp/maxtemp monitoring. This would need to change in the
future if chamber heating became a feature.

Table is very very similar to old 104-GT2 so I added only the name and recycled old ID