Fixes error
Only remove actualy failed blocks from setBlockIndexValid
Only keep setBlockIndexValid entries that are possible improvements
Reject transactions with excessive numbers of sigops
Add helptexts for -whitelist and rpc prioritisetransaction and switch to bitcoin instead of satoshis
Add a new checkpoint at block 295,000

Block 295,000 seems to meet the criteria of a reasonable timestamp and
no strange transactions. 295,000 is the current block height in the
bootstrap.dat torrent provided by jgarzik.
net: add SetSocketNonBlocking() as OS independent wrapper
additional test for OP_SIZE in script_valid.json
script tests: BOOLAND, BOOLOR decode to integer

unlike other boolean checks, arguments >5 bytes invalidate the script
script tests: values that overflow to 0 are true
script tests: value with trailing 0x00 is true
script test: test case for 5-byte bools
script tests: add tests for CHECKMULTISIG limits
remove an unneded .c_str() in OpenNetworkConnection()
CBloomFilter::clear() method
Bugfix: make CCoinsViewMemPool support pruned entries in underlying cache
Fix typos in comments (missing i's).
Merge pull request #4575

ad08d0b Bugfix: make CCoinsViewMemPool support pruned entries in underlying cache (Pieter Wuille)
Merge pull request #4496

5734d4d Only remove actualy failed blocks from setBlockIndexValid (Pieter Wuille)
Add missing FindNode prototype to net.h

Also make the argument a const std::string & instead of pass-by-value.