remove an unneded .c_str() in OpenNetworkConnection()
Add missing FindNode prototype to net.h

Also make the argument a const std::string & instead of pass-by-value.
pyminer: Fix memory leak, refactor to be more pythonic, maintainable, and possibly faster

Pull #4483.

Note that pyminer is not currently functional due to the removal of
getwork in cf0c47b.
Merge pull request #4567

f469f79 remove an unneded .c_str() in OpenNetworkConnection() (Philip Kaufmann)
Merge pull request #4584

0430c30 Add missing FindNode prototype to net.h (Wladimir J. van der Laan)
replace ComputeMinWork with CheckMinWork
Remove redundant pblock->nNonce = 0
Move UpdateTime to pow
Move CBlockIndex::GetBlockWork() to pow::GetProofIncrement(nBits)
Simplify and rename CheckWork to ProcessBlockFound
Encapsulate proof of work generation in pow
Encapsulate CBlockHeader fields for most pow calls
Create Proof class
Make fields private