Issue 13 add license
Added Apache License 2.0 to the project
In principal it is advisable to also add a small preamble to each file:
Copyright 2021 University of Oxford, Oxford, UK
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
But we should probably wait until the changes are not so fast and furious.
Edited by Sean Fitzgibbon