Refactoring imagery-search base map selection.

[sharkinsspatial]

Refactoring imagery-search to support improved testability, better follow Redux best practices and adhere to Mapbox GL state management best practices closes #88.

[tombh]

Great! Really nice coding style; clear, well thought out and nice refactoring. You clearly know your React :)

One thing that could have been good would be to have used the same testing approach as oam-browser, ie mocha and sinon (oh, actually you'd only see sinon if you looked at my unmerged branches). It's not a big deal, tape and babel-require-plugin are great too. But it would just make things easier when merging back into oam-browser. Don't feel like you have to change this though. BTW, similarly I hope that imagery-coordination-api will be merged into oam-catalog.

Anyway, looks great, nice work :)

[sharkinsspatial]

Updated .travis.yml to force use of Trusty environment rather than Precision. CI builds are now passing correctly. One additional note on updating Mapbox GL JS maps via style diffs. There is some code in this pull request that can be simplified once this upstream Mapbox GL JS issue fix is released.

[smit1678]

@sharkinsspatial Feel free to assign this to me when this is ready to be reviewed and merged (we can use that method for future PRs as well).

[smit1678]

Closing out in preference for a new PR, #141