Merge pull request #4748

ad49c25 Split up util.cpp/h (Wladimir J. van der Laan)
f841aa2 Move COIN and CENT to core.h (Wladimir J. van der Laan)
6e5fd00 Move *Version() functions to version.h/cpp (Wladimir J. van der Laan)
b4aa769 Move S_I* constants and MSG_NOSIGNAL to compat.h (Wladimir J. van der Laan)
af8297c Move functions in wallet.h to implementation file (Wladimir J. van der Laan)
651480c move functions in main and net to implementation files (Wladimir J. van der Laan)
610a8c0 Move SetThreadPriority implementation to util.cpp instead of the header (Wladimir J. van der Laan)
f780e65 Remove unused function ByteReverse from util.h (Wladimir J. van der Laan)
121d6ad Remove unused alignup function from util.h (Wladimir J. van der Laan)
d1e26d4 Move CMedianFilter to timedata.cpp (Wladimir J. van der Laan)