added fixtures for header parser
building up

added chai-as-promised and mocha-as-promised
fixed some property hiding in DefIndex
imported tests for DefInfoParser from tsd-deftools
started adding more tests
added sha shortening util
improved INFO
various small edits
building up

moved fixtures to appropriate module subfolders
moved module test source to src subfolder
added many assertion helpers to ./test/helper.ts
added first batch of tests with externalized case data
added local loggers to some classes
edited TODO.md
various small edits