Add info about license and author

Signed-off-by: Shawn Webb <shawn.webb@hardenedbsd.org>

README.md

 # liblattzfs
 
+* License:	2-Clause BSD License
+* Author:	Shawn Webb
+  [shawn.webb@hardenedbsd.org](mailto:shawn.webb@hardenedbsd.org)
+
 This is a tiny little wrapper around libzfs so that applications in
 ports don't have to depend on all the weird, funky CFLAGS.