SLAC interface for generating physics graphs

Current versions

topdrawer requires the following formulae to be installed:
gcc 7.3.0_1 GNU compiler collection
ugs 2.10e SLAC Unified Graphics System

Recent formula history

David Hall Travis-CI uses brew test-bot Copied .travis.yml from brew-tap-new script. This should make for quicker testing, because only the edited formula is tested. Also moved formulae to Formula folder.
David Hall Style changes
Dmitry Kalinkin topdrawer: new formula

Formula code at GitHub