Move voting pool code to votingpool package

Conflicts:
	waddrmgr/internal_test.go
Make tests run again
Move voting pool test helpers to votingpool package
Experiment: Expose crypto service functions on manager instead of returning the keys
Remove ManagedAddress dependency
Remove crypto functions from votingpool_bridge as they are now defined on master
Update encryption/deryption function comments
Remove obsolete internal test functions and update tests accordingly
Add comment
Add comment explaining purpose of votingpool_bridge.go
Add two other comments
Merge pull request #66 from larshesel/move-vp-into-own-package

Move vp into own package