This introduce a new internal package to deal with the explicit
clearing of data (such as private keys) in byte slices, byte arrays
(32 and 64-bytes long), and multi-precision "big" integers.
Benchmarks from a xeon e3 (Xor is the zeroing funcion which Bytes
replaces):
BenchmarkXor32 30000000 52.1 ns/op
BenchmarkXor64 20000000 91.5 ns/op
BenchmarkRange32 50000000 31.8 ns/op
BenchmarkRange64 30000000 49.5 ns/op
BenchmarkBytes32 200000000 10.1 ns/op
BenchmarkBytes64 100000000 15.4 ns/op
BenchmarkBytea32 1000000000 2.24 ns/op
BenchmarkBytea64 300000000 4.46 ns/op
Removes an XXX from the votingpool package.
