This commit clarifies license of the software replacing “BSD3” with more
conventional “BSD 3 clause”.
Another change is addition of the third clause originally missing in
license of Parsec (which is licensed under BSD 2 clause license). The
addition of the third clause in form:
* Neither the names of the copyright holders nor the names of
contributors may be used to endorse or promote products derived from
this software without specific prior written permission.
does not violate original BSD 2 clause license effectively making it BSD
3 clause license (which I find preferable).
