Add "Series Round" sutra for ICO strategy

[syrohei]

• If a token creation event has been end, Proof of Donation executes a single Token creation event. but Some ICO project implement a second ICO strategies. RICO take off it easy as a simple execute.

function executeNextSeries() onlyOwner() returns (bool)  {}

• the fail of the DAO, function split Can be called while propose submitted.