WIP: more functionality for the c interface

CMakeLists.txt

include/CMakeLists.txt

include/caosdb/authentication.h

include/caosdb/connection.h

include/caosdb/utility.h

include/ccaosdb.h

src/caosdb/authentication.cpp

src/caosdb/connection.cpp

src/ccaosdb.cpp

src/ccaosdbcli.c

src/cxxcaosdbcli.cpp

test/CMakeLists.txt

test/test_ccaosdb.cpp

test/test_connection.cpp

test/test_utility.cpp