* use es6 exports in fixtures
* use es6 exports in test_utils
* use es6 exports in src/ui
* use es6 exports in src/utils
* use es6 exports in src/server
* use es6 exports in timelion
* use es6 exports in core plugins, but not console
* use es6 exports in console
* use es6 exports in src/cli
* use eslint --fix for no-extra-semi rule
* selectively disable kibana-custom/no-default-export
* replace define() with exports
* clean up some object exports
in these cases, named exports are the better replacement
* use es6 exports in src/optimize, where possible
* fix uses of named exports
* fix some imports in console
* revert postcss optimizer to module.exports
* [timelion] put shared code in common directory
* fix url module export
don't export as default, rely on the named export
* convert define modules in src to export
* convert ui-bootstrap to cjs module
* lint webpackShims
no reason not to, they pass when the no-var rule is disabled
* fix new code not using es6 exports
* fix some straggling exports
- Add 'test:visualRegression' grunt task.
- Run 'test:visualRegression' as part of npm script 'test'.
- Add 'clean:screenshots task'.
- Clean screenshots/session when funtional tests are run.
