Improved feedbacks and game flow

Couple additions this week:

• Added a neat Game Summary popup between periods and at the end of games, showing all goals, assists and shots in more detail
• Off-screen indicator arrows for human-controlled players
• Added a black trail to the puck
• After goals, players go smoothly to center ice instead of spinning around weirdly
• Improved each player's strengths icons in their listings
• Increased the speed of league creation