PID Controller for Control Rod Level Management & various other changes

[Kasra-G]

• New PID Controller to moderate the control rod insertion logic
  • Does its best to hit both the RF/T target and the buffer fill target
  • should be more responsive and have less overshooting in most cases
• Fixes a unit issue with Bigger Reactors temperatures
• Averages readings over the past 2 seconds to help with readability in cases where power consumption is sporadic
• Changed Control Rod graphic to be white on yellow background
• Updated README

Would appreciate if anyone would like to test out these changes before I roll it out to everybody

[Kasra-G]

Attempts to fix

• 10

Fixes:

• 13

• 7