adds basic structure for multiSigWallet part of sprint
adds all test for multiSigWallet
finishes all tests for 2/3 multiSig wallet
adds extra credit specs for multiSigWallet(n, m)
fixes errors for (spec/)multiSigWallet
clarifies spec/Transaction
adds basic structure for multiSigTransaction.js
adds tests for multiSigTransaction.js
Merge pull request #5 from kayellpeee/master

adds multiSignature section of sprint