Third party error resolution

[LandauSchwinger]

#10
First point of issue is solved by changing CMAKE_SOURCE_DIR to CMAKE_CURRENT_SOURCE_DIR in main CMakeLists.txt and similar modifications inside knp/python-framework/CMakeLists.txt (there was also some actions with LICENSE, VERSION and REAME files).
Second point was solved by changing how I add KNP via CPM:

set(CPM_KNP_SOURCE FALSE)
set(KNP_DOWNLOAD_DEPENDENCIES OFF)
set(KNP_BUILD_THIRD_PARTY OFF)

CPMAddPackage(
    NAME knp
    GITHUB_REPOSITORY LandauSchwinger/knp
    VERSION third-party-error
    GIT_TAG 6283b3c31d2526e7c80cf9e3ccf887f16cd905c0
    OPTIONS
        "KNP_BUILD_THIRD_PARTY OFF"
        "KNP_DOWNLOAD_DEPENDENCIES OFF"
    EXCLUDE_FROM_ALL YES)

By this KNP didn't copy several times inside third-party folder of itself.