Changes:
Update default start page with more useful functions.
Update appearance of status buffer for visual consistency.
Fix buffer listing mode.
Implement download manager support in Electron port.
Implement after-download-hook.
Simplify download manager architecture.
Update colors of pre and code blocks.
Fix exiting, clean up all dangling threads.
Fix message buffer color/initialization on startup.
Fix vi unfocusing of elements after exiting insert mode. Users can now use the unfocus-current-element command bound to esc in vi normal mode.
Automatically refresh download page on download completion/cancellation.
Limit maximum size of link/element hints.
Fix rendering on Wayland systems.