Touchup spacing; reorder tests, notes; add another example for changing lcd_calc.ary & calculation
Add notes, test demonstrating re-use of .calculate_lcd without a prior call of .reset_divisors
Begin refactoring sequenced-number-set tests into a describe block
Initialize LCDCalc with a given number_set
Rework test suite; reword test descriptions; make use of LCDCalc's initialize-with-array