Add Apache 2.0 License
Merge pull request #2 from esl/add-license

Add Apache 2.0 License
Update doc with doxygen 1.8.7

Script:
  $ rm -r doc/html; cd doc && doxygen
Merge pull request #3 from esl/update-doc

Update doxygen doc
Merge remote-tracking branch 'aman/master' into make-doxygen-doc
Add make targets for building and cleaning doc

doxygen is required for building the HTML doc.
Delete HTML doc as it can be generated using 'make doc'

The doc was deleted running 'make docclean'.
Merge pull request #1 from esl/make-doxygen-doc

Add LICENSE and add make target for generating HTML doc