LaserGRBL Versions Save

Fix https://github.com/arkypita/LaserGRBL/issues/1969

This release literally changes nothing in how LaserGRBL works. I only have reverted some minor changes if project and solution files, to be sure the executable will be compiled as older 5.x versions.

LaserGRBL v6.1.0 was build to request Microsoft .NET Framework 4.8 but this caused problems with some PCs with outdated Windows. This version restores the use of the 4.0 libraries, available on most PCs, and solves the problem of some users for whom LaserGRBL 6.1 no longer worked.

Some new machines comes out with a controller firmware that is called "SimpleLaser". It is an unofficial and undocumented fork of Grbl firmware, that have some issues with LaserGRBL configuration reading. This version fix this issues and make able to read configuration even with SimpleLaser firmware.

This release changes some low-level libraries with which LaserGRBL measures time intervals, inserting some additional checks that allow to intercept and correct the big time jumps that occur when the system is put into standby or in hibernation while LaserGRBL is running.

This version restore a behavior of v4.9.4 where, if it is not possible to read the configuration from the machine (rare and wrong case, but existing) a value of 1000 is assumed for $30 Max PWM. This fix some issue that few user is having using v5.x

Note to the reader: it's not really a LaserGRBL bug! If configuration can't be read is a problem of the machine firmware. I only put a patch on it!