SlothPackage: splited package command into install and export command
SlothAddTarget: fixed minior issues in AddTarget module
Include all commands in generated SlothConfig.cmake file
Sloth: the project command does now generate a version variable
Enable cmake policy for 3.0
SlothAddTarget: removed emulation of interface targets for CMake 2.8.12
Sloth: added configure src to CMAKE_CONFIGURE_DEPENDS property