bump cmake minimum version to 3.10

bump version for fixed tests

bump version to 6.4.5

fix pkg-config placement

make cmake install also install version file

fix group GetErrorMsg handling

revert 6.4.0 changes

try to fix up the cmake install, so this is compatible with find_pack…

…age and ExternalProject

add operator * and operator -> to most types; bump version

version bumps