[WIP] Dropdown component

[jscheiny]

Changes proposed in this pull request:

This PR introduces a simplified Select style component in the form of Dropdown which makes it easy to render quick lists of selectable items. Like other Select components, this component is always controlled and uses similar API designs. One simplification that this component makes is that for string and number values, it automatically infers how to render those into text. For non-serializable items, it provides a call back to render each list item into text.

[svc-palantir-github]

Format

Build artifact links for this commit: documentation | landing | table | demo

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