Fix point_to_hex function

point_to_hex should specify a minimum size of 64, not 32. 

The sign function of ECC was returning a large signature regardless of the actual size of the signature. sig.raw[:siglen.contents.value]   is better as it limits the returned signature to actual signature data (not null padded data).

Added decryptFast(msg,cryptor) to bitcoin.py. This function can decrypt 24 times faster because it doesn't have to recreate the cryptor object.

Added code to OpenSSL.py so that OpenSSL can be used to do point multiplication as this is much faster than using the arithmetic file.

Added code to look for libeay32.dll within a temporary folder if it exists. Vitalik, you may not be interested in this. I have it here so that it looks for libeay32.dll within the temporary folder than pyInstaller creates when it runs.