for some packages that use pkgconfig: use the static list of headers and libraries for the sake of completeness

  - CPPCHECK_EXECUTABLE stores the cppcheck executable path
    - look for cppcheck executable in PATH env. var. or CPPCHECK_DIR/bin or CPPCHECK_BINDIR (env. var. or CMake variables)
  - CPPCHECK_VERSION stores the version

Add a hint to help Cmake to find the correct python version(python2)

See merge request !1