HFR history enhancements

[Stanley Dimant]

Multiple proposed enhancements: 1. Dynamically alter the Y axis based on recorded values (when you have more than 400 stars you can't see the end anymore) 2. Add a legend which value is actually star count and which is HFR 3. Enable a scrolling history or at least being able to save more values to see HFR history over time

[Stefan B]

Partial Fix Issue #41 - Enable Legend for HFR History

→ <<cset a80f59266803>>

[Stefan B]

Partial Fix Issue #41 - Increase size of history to 100

→ <<cset 39072af58057>>

[Stefan B]

Partial Fix Issue #41 - Auto scale of axis

→ <<cset ab6bd3833c81>>