Remove defaults for ReadConsistency and WriteConsistency

[patriknw]

• Removed constructors/apply with default value (ReadOne/WriteOne) for consistency in Get, Update and Delete messages
• The reason is that there is no good default. It depends, and is something that should be thought of by the user.
• WriteOne renamed to WriteLocal
• ReadOne renamed to ReadLocal
• WriteTwo and WriteThree removed, in favor of WriteTo(n)
• ReadTwo and ReadThree removed, in favor of ReadFrom(n)
• timeout parameter moved to ReadConsistency and WriteConsistency class. It is not appropriate for WriteLocal/ReadLocal. This also simplified the API.

Fixes #47

[hseeberger]

This looks awesome!