Add new license detection rules for BSD-3-Clause

[pombredanne]

https://github.com/sfilippone/psblas3/commits/development/LICENSE license is detected correctly as a BSD-3-Clause, but could benefit from some improvements:

• https://raw.githubusercontent.com/sfilippone/psblas3/d2fba9e952807b0258360c7b49714a0e9f626a3b/LICENSE
• https://raw.githubusercontent.com/sfilippone/psblas3/316561c34559d7e10f9ec96d11f30ede0c95269e/LICENSE
• https://raw.githubusercontent.com/sfilippone/psblas3/1748dac50f3dc52b1dc33034473d97ccb45eb13e/LICENSE

.... are each small variations that we should detect exactly.

From sfilippone/psblas3#37

[kumarasantosh]

Hi @pombredanne ,
I'd like to work on this. My approach will be to fetch all three LICENSE variants from the referenced commits, diff them against the canonical BSD-3-Clause text to isolate the exact differences, and add dedicated .RULE + .LICENSE files for each variant under src/licensedcode/data/rules/. Each rule will be validated to produce an exact match (matcher: 2-aho, score=100, coverage=100) with no regressions in the existing test suite before submitting a PR.