make name_ protected in InterestRateIndex so that SwapSpreadIndex can modify it
keep rho aways from +/- 1.0, add comment for later inspection
fix computation for negative strikes
fix condition on number of integration points
introduce observer for cms pricer taking care of flushing the cache,
replace some expressions by predefined constants,
fix swaplet price (add discounting factor),
register with correlation quote
fix transformation of guess (this line belongs to the code commented out above)
make sure that parameter guess is only updated when quotes change (and not on other notifications, because e.g. a beta recalibration may be broken unintentionally)
cleanup
add 3rd example
use smarter guesses (adapt alpha to beta level, limit nu to more realistic levels)
if not given deduce the acceptance level from the max error (for non vegaweighted mode this does not change the default value actually, for vegaweighted mode it is reduced)