added FixedRateBond mode with definition of clean price instead of zero rates or yield.
Merge branch 'master' into FixedRateBondWithPrice
Merge branch 'master' into FixedRateBondWithPrice

Conflicts:
	R/RcppExports.R
	inst/include/RQuantLib_RcppExports.h
	src/RcppExports.cpp
fixed help for FixedRateBond with clean price
Merge branch 'master' into FixedRateBondWithPrice
added examples and test for FixedRateBond with clean price