Better filter bookmarking/sharing

[lemeryfertitta]

In #70 @gardaholm added the ability to pre-populate an angle in the filter view. This allows for more convenient bookmarking. There is no UI for this currently, users would just have to know about this feature and manually adjust the URL.

I think that there is an opportunity to extend this concept further and save entire filters for bookmarking and sharing. For example, a "Share" button that creates a URL containing all of the parameters to pre-populate all of the filters with.

[brmnjsh]

@lemeryfertitta I'll take this on