fix livereload

[jelhan]

Allowing connections and script source required by livereload feature was broken by configuration refactoring. This fixes it and adds tests.

This PR is based on #104. It should be merged afterwards.

[rwjblue]

Ready for a rebase now that #104 has landed

[jelhan]

Rebased and fixed the test that were failing due to leaking state.

[jelhan]

This is not ready yet. This had moved the calculation of config to serverMiddleware hook but that's only executed on ember serve but not on ember test and ember build. Will need to refactor to calculate the config in a more common hook (e.g. included as before) and handle the livereload configuration separately.

[jelhan]

Pushed a new implementation. It's a total rewrite of this PR. I guess a new review + approval is required.

It does not treat live reload options as part of config anymore. They are calculated independently from other config in serverMiddleware hook and cached for contenFor hook. Live reload should be disabled if serverMiddleware hook is not executed cause live reload depends on express server. Luckily contentFor hook is executed after serverMiddleware hook.

Before my rewrites of all that stuff live reload was calculated in contentFor and serverMiddleware hooks independently:
https://github.com/rwjblue/ember-cli-content-security-policy/blob/4aabfa50496c720a76fa1e689ea43c04a40be875/index.js#L122-L129
https://github.com/rwjblue/ember-cli-content-security-policy/blob/4aabfa50496c720a76fa1e689ea43c04a40be875/index.js#L173-L184

This introduces inconsistency between both which may result in broken live reload support if CSP is put in meta tag. Especially the contentFor hook ignored the live reload host option cause that value wasn't available trough environment variables.

[jelhan]

Squashed commits.