Initial revision of CPU miner.

NOTE: non-functional (incorrectly thinks it finds solution, too quickly)
Add README and license info.
Add some code comments.
Clean up proof-of-work checking,
attempting to address find-solution-too-fast problem.
Add timing info.  Remove BIGNUM PoW checks.
Add command line parsing, and multiple threads.
Code movement.  Update stats counter more frequently.
Remove byte reversing in submit_work()
sha256: Assume that input is already big endian.
Clean up protocol debugging output, and other cleanups.
sha256: note about bitcoin input data
Convert over to autotools.  Release version 0.1.
Do not build sha256_generic module separate from cpu-miner.c.  Version 0.1.1.
Add GPLv2 header.
Small cleanups and comment additions.  Don't sleep after proof of work found.
RPC URL, username and password become arguments,
rather than compile-time constants.
Remove unused OpenSSL dependency.

Also, turn a few strings into #define'd constants.
Allocate work struct once, on stack, rather than alloc+free for each getwork.
scanhash micro-optimizations

* don't bother returning nonce, we only need success/fail boolean
* don't needlessly read nonce pointer data, for each loop
sha256: Remove unused include arpa/inet.h