Update Icons to Use SVGs

1. Status Quo

Uses Material Design Iconic Font. Implemented as font and CSS files distributed manually that must be made available via HTTP. A [:span] contains a special character code that maps to an icon in the font.

Upsides

• No breaking changes.
• No work to complete.
• Supports old browsers (e.g. Internet Explorer, Android prior to 4.4 etc) although we probably don't care anymore.

Downsides

• Must be manually deployed as a separate file. Not pulled in automatically with the JAR dependency and :require. Esp bad for upgrade experience or new users expecting the library to "just work".
• Limited styling compared to SVG, in theory.
• Limited to icons supported by the Iconic font distribution.
• At some point upstream will probably stop shipping font files for icon sets, as it is effectively an obsolete technique now with widespread SVG support in browsers.

2. Material Design SVG Icons - Manual

Would use Material Icons as SVG represented as hiccup in reagent view functions.

Upsides

• Pulled in automatically with JAR dependency and :require. No extra files to deploy.
• Full CSS styling available, but would we actually use it ?
• Opens up possibilities of animations and transitions.
• Can include any SVG, not limited to a pre-packaged font.
• Supports any relevant browser today (i.e. MS Edge, Chrome, Firefox, Safari etc)

Downsides

• As the library maintainer, to upgrade or add icons from the upstream SVG icon set would be a manual process.
• Tree shaking would not be possible or a breaking API change would be required.

3. Material Design SVG Icons - Automated

• Same as 2.
• Use Material Icons Git sources
• Script conversion of a directory of SVG files to a ClojureScript namespace to automate maintenance. E.g. using clojure.xml and zippers.

Start by locating the current Material Design Iconic Font CSS and font integration, then inspect the Reagent view functions that render icons. Compare the manual and automated Material Icons SVG approaches described in the issue and establish which migration path is intended. Done should include the selected SVG icon implementation being packaged with the JAR without separate asset deployment.