0.1.0-pre.4

• requires elixir version 0.12.2
• use macroses for high-level api, thanks to @aidansteele
• registering default client for high-level api, for use it without client_pid, @aidansteele
• new elixir send message api
• new default arguments syntax, thanks to @drouchy

new pub/sub api

• new pub/sub api
• fix version

early pub/sub api

• Early pub/sub implementation
• Enhance test coverage
• Add usage as mixin