Enforce max block number.
RFC6330 lets you have 256 blocks at most. Check at
the interleaver definition.
The C interface did not check for correct C++ initialization.
fix that, too.
Signed-off-by: 
Luca Fulchir <luker@fenrirproject.org>
RFC6330 lets you have 256 blocks at most. Check at
the interleaver definition.
The C interface did not check for correct C++ initialization.
fix that, too.
Signed-off-by: Luca Fulchir <luker@fenrirproject.org>