remove common package entirely
rename ZeroNetwork to DebugNetwork
underlying keys are no longer exported in siacrypto
refactor siacrypto
move longhair functions to erasure pacakge
move longhair to erasure/longhair
update documentation within erasure package
more thorough error checking in siacrypto
cleaned documention in siacrypto
more thorough testing of signatures.go
basic testing for erasure package
switch to 9 pieces instead of 8
Merge pull request #131 from DavidVorick/reorg-safe

Reorganization
Fixes #86 and resolves #127.