Tasks: fix bug in cancel method. Add currenTime method.
Tasks: fix bug in cancel method. Add currenTime method.

tempbottle/raft.js,kanaka/raft.js,kanaka/raft.js,kanaka/fuzzy-raft,kanaka/fuzzy-raft,moquist/raft.js,kanaka/fuzzy-raft,moquist/raft.js,tempbottle/raft.js,kanaka/raft.js,kanaka/fuzzy-raft,kanaka/raft.js,moquist/raft.js,moquist/raft.js,kanaka/fuzzy-raft,kanaka/raft.js,tempbottle/raft.js,moquist/raft.js,tempbottle/raft.js,tempbottle/raft.js