Fix XTEA endianness issue, fix issue #4
Fix XTEA endianness issue, fix issue #4

The code still needs testing on two systems with different endianness!

libcsp/libcsp,GomSpace/libcsp,kubostech/KubOS,libcsp/libcsp,satlab/libcsp,Psykar/kubos,Psykar/kubos,GomSpace/libcsp,Psykar/kubos,satlab/libcsp,pacheco017/libcsp,marshall/libcsp,Psykar/kubos,satlab/libcsp,Psykar/kubos,Psykar/kubos,Psykar/kubos,pacheco017/libcsp,marshall/libcsp,pacheco017/libcsp,kubostech/KubOS,pacheco017/libcsp,GomSpace/libcsp,marshall/libcsp