v0.3.0 - Flow

• [Added] The flow machenism that allows you to push information from the current state directly to the next state. The variable self.flow_in contains the information from the previous state and you set self.flow_out to hold information that goes to the next state. The flow is not carried over unless specified by the state. For machine,sequential states, flow are passed into low-level states.
• [Changed] Restructure the code, such that core is in a sperate module instead of using the same file. Board is now in core instead of it's own namespace.
• [Added] Other tests that check for consistency of implementation.