[ACTIV-62] - Temporary estimate of next dividend date as 1 / dividends per year if next_div_date is in past
[PLAT-5376] Limit the size of thread pool that live data client uses
[PLAT-5362] Roll-Geske-Whaley model

Also includes [PLAT-5363] Analytic Greeks for RGW model
[PLAT-5378] Removing DividendFrequencyCodeCalculator which is actually specific to one provider, and clarifying docs.
[PLAT-5378] Cope with any number of dividends per year
[PLAT-5378] Default to 4 dividends per year if no market data
[PLAT-5376] Fix error in previous commit
[PLAT-5378] Numeric dividend frequency is always a double from market data layer