Versions check between IPT and the engine

[micheles]

Right now the job.ini contains a line like

# Generated automatically with IPT at Sun, 26 May 2019 13:56:03 -0000

but not a version number. We probably need to do something like the QGIS plugin does: use the same version number between engine and IPT so that the engine can check if there a version mismatch. Notice that a mismatch is not an error, newer versions of the engine normally work with files generated by and old IPT, but in the other direction at least a warning should be raised.

[nastasi-oq]

I strongly prefer decoupling IPT version and supported Engine format version (that can follow the Engine version strictly if you like but will be better if there was a explicit API versioning at Engine side because maybe between 2 contiguous versions nothing was changed.