Make MFT work on either 1.8 or 1.9

Update Checkers.cs

* Changing checkers versioning back because still going to be one or more updates for 1.8

Fixed MLI field issue

* Fixed issue where if _numberOfAddedMLILayers max value == min value it would break PAW for all other fields appearing after.

Merge pull request KSP-RO#236 from arthurp/master

Update for KSP 1.8

Compile for KSP 1.7.3

* Compile for KSP 1.7.3

Changed checkers target version to 1.6

* Changed checkers target version to 1.6 (and re-release for 1.6)

Revert "Update RealFuels.csproj"

This reverts commit f98c919.

debugBoilOffPAW = true by default

* debugBoilOffPAW = true by default

Update Readme_RF.txt

One missing bracket...

* One missing bracket...