Use misc methods of avoiding unnecesary header includes.
Replace int typedefs with int##_t from stdint.h.
Replace PRI64[xdu] with PRI[xdu]64 from inttypes.h.
Normalize QT_VERSION ifs where possible.
Resolve some indirect dependencies as direct ones.
Remove extern declarations from .cpp files.
class template base_uint had its own private lookup table.
This is saving 256 bytes per instantiation.
The result is not spectacular as bitcoin-qt has only shrinked of
about 1Kb but it is still valid improvement.
Also, I have replaced a for loop with a memset() call.
Made CBigNum::SetHex() use the new HexDigit() function.
Signed-off-by: Olivier Langlois <olivier@olivierlanglois.net>
One of the test cases currently aborts when using gcc's flag -ftrapv, due to
negating an INT64_MIN int64 variable, which is an undefined operation.
This will be fixed in a subsequent commit.
