Added Inspector Window
Added Inspector Window

- 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, log error instead of crashing
- Events window resizes to fit full column data

missionpinball/mpf-monitor