Add progression from small to large constellation for Star Map

[K-Meech]

For #17 (see new info on adaptive difficulty from David on this issue)

Adds:

• Game starts with a small constellation (5 stars)
• After winning two games in a row with the max sequence length (=5), upgrades to the large constellation
• Removed the set number of guessed sequences required to win. Now the game ends on reaching the max sequence length (= number of stars in constellation) OR after guessing a sequence correctly after having the length downgraded. This allows longer sequences to be shown (up to a length of 10)
• Fixed issue with star selection, noted on this comment