- fixed result-length for sha256

- moved testbag for v0.97 to new subdir
- added v1.0 based testbag including new recommended sha512 manifest files

- removed superflous nullptr-check after new() in checksum_of_file()
- fixed problem with moved string in testbag.cpp check_validation()

- set_BaggingDate() allows time_t now

- set_BagSize() uses unsigned long int now

- renamed create_new() to add_payload()
- added add_bagmetadata()
- added add_fetchfile()
- added add_othertags()
- using default values in Bag-constructor
- enhanced example create_a_bag.cpp

- validate() checks for at least one checksum file

- added testcass

- renamed has_oxum() to has_PayloadOxum()
- renamed get_bagmetadata() to get_metadata()
- renamed has_bagmetadata() to has_metadata()