Contains breaking changes, the most significant of which are:

• Moves the runtime client build directory to a "user data" directory rather a directory
  where IDOM's code was installed. This has the advantage of not requiring write
  permissions to rebuild the client if IDOM was installed globally rather than in a
  virtual environment.
• The custom JS component interface has been reworked to expose an API similar to
  the createElement, render, unmountComponentAtNode functions from React.

Issues Fixed:

• File Input Handling #375
• find_builtin_server_type should return Optional server type #394
• Errors in event handlers cause server to crash #401

Highlighted Commits:

• add try/except around event handling - f2bf589
• do not call find_builtin_server_type at import time - e29745e
• import default from react/reactDOM/fast-json-patch - 74c8a34
• no named exports for react/reactDOM - f13bf35
• debug logs for runtime build dir create/update - af94f4e
• put runtime build in user data dir - 0af69d2
• change shared to update_on_change - 6c09a86
• rework js module interface + fix docs - 699cc66
• correctly serialize File object - a2398dc