Add Gamma Correction, Inspector Window, plus a ton of useful features

[kylenahas]

Summary of features:

• Gamma Correction for lights
• Alternating row colors for tree views
• Inspector window now exists, contains tools for mpf-monitor
• Toggling Inspector mode on disables switch events to mpf
• Inspector Enabled gives access to all elements of the last selected item via callback
• Device sizing now individually adjustable
• Slider and Spinbox for changing device size
• Saves new size only if it makes sense (non-default)
• When a device that already exists is added to pf, remove old device
• Events window resizes to fit full column data
• Ability to remove a device from the playfield
• Ability to change default device size
  • Changes all devices without custom size
  • Can re-set device size to default
• Finer control over device size
• Inspector window now can be tabbed
• Added "Monitor Inspector"
  • Includes checkboxes to show/hide windows
  • Function to quit mpf-monitor when one window is closed

[kylenahas]

Resolves https://github.com/missionpinball/mpf-monitor/issues/24 Resolves https://github.com/missionpinball/mpf-monitor/issues/23

[kylenahas]

Preview of the inspector window (device inspector tab)

Monitor inspector tab

[jabdoa2]

Wow that is awesome! Thanks for all the work.