Integrate with the state of the Ethereum's blockchain

[loiluu]

From @loiluu on September 21, 2016 5:4

One way to improve the performance of the symbolic execution is to consider the existing blockchain state in the execution environment. For example, if a contract calls a function a = contractB.getSomeData() we can fetch the blockchain state to see what the value that contractB.getSomeData() would return and assign the value to a, instead of using a new symbolic value for a.

Copied from original issue: ethereum/oyente#3

[loiluu]

@inian if possible, please update the status of this PR!