v0.1.1

This release introduces

Reworked connections system:

• get rid of Signal trait: events now associated with entities using filter functions (EntityEvent)
• it is possible to connect from any event to any handler (not only entity-based)
• get rid of connect! macro (use run! instead)
• on:event accepts closures or handlers (closures wrapped with run! macro)
• all connections may be done outside widgets
• see Connections README section and example

Reworked Elements system param

• make Elements act like Commands-like cheap readonly system param
• index elements with id to Entity, respect index in Elements.select()
• move elements invalidation to separate system
• order invalidate/ess-apply/fix-text-height systems
• see Modifying UI README section and party-editor example