Updated the minimum required version of CMake to 3.15
Removed old policies set to OLD, since those referred to CMake <3
Fixed all CMake warnings
project version is not hardcoded anymore, but retrieved from git metadata using git describe
Versions for releases won't change, they should still follow basic semantic versioning (i.e. X.Y.Z), but for a development version they will appear as e.g. v3.00.03-132-gc8941a5-dirty which means that the last release was 3.00.03, we added 132 new commits from that point, the last commit hash is c8941a5 and the current directory tree is not clean.
git describeVersions for releases won't change, they should still follow basic semantic versioning (i.e. X.Y.Z), but for a development version they will appear as e.g.
v3.00.03-132-gc8941a5-dirtywhich means that the last release was3.00.03, we added 132 new commits from that point, the last commit hash isc8941a5and the current directory tree is not clean.Closes #103