Merge pull request #1815 from ProjectMirador/add-overlapping-windowing-system

__tests__/src/actions/window.test.js

__tests__/src/actions/workspace.test.js

__tests__/src/components/App.test.js

__tests__/src/components/Window.test.js

__tests__/src/components/Workspace.test.js

__tests__/src/components/WorkspaceElastic.test.js

__tests__/src/reducers/windows.test.js

__tests__/src/reducers/workspace.test.js

package.json

src/components/App.js

src/components/Workspace.js

src/components/WorkspaceElastic.js

src/config/settings.js

src/containers/Window.js

src/containers/WorkspaceElastic.js

src/state/actions/action-types.js

src/state/actions/window.js

src/state/actions/workspace.js

src/state/reducers/windows.js

src/state/reducers/workspace.js