Multiple handlers (MD5, SHA-1, SHA-2-256, etc.)

This release sports more handlers for message digest algorithms supported by JDK 8+.

The following is a list of possible handler names:

Message Digest	handlerName Parameter	Default checksumFile	Note
MD5 *	message-digest	MD5SUMS *	* default is MD5, overwriting is possible
MD5	message-digest-md5	MD5SUMS
SHA	message-digest-sha-1	SHA1SUMS	"SHA" in JDK refers to the SHA-1 algorithm
SHA-256	message-digest-sha-2-256	SHA256SUMS	SHA-2
SHA-512	message-digest-sha-2-512	SHA512SUMS	SHA-2

Initial release

This is the first release of the message-digest-assembly-handler.
Enjoy!