* Add the $Hooks$Rounding parameter to hold the RoundingHelper
  object (in the constructor, a named list of rounding specs
  can be given, which will be coverted to a RoundingHelper by
  the InsuranceTariff constructor).
* Use the helper in most places where rounding intermediate values
  makes sense
* Each use of the rounding helper is indicated by a separate ID, so
  each rounding occurrence can (and must) be configured separately
* By default, no rounding occurs, unless a rounding accuracy (nr of
  digits) was explicitly configured for the ID
* Add documentation

Clean up minor mistakes / typos; Improve test case generation (include code to expoert sample contract to Excel)

Add gammaInZillmer Parameter as a feature (i.e. gamma costs included in Zillmer premium, but not beta costs)

* Add return value documentation
* use tempdir for output in examples
* Quote application names

V0.0.5: Fix warnings / docs errors, add vignette about company-specifig implementations (RStudio template)

* implement copying template files (placeholer replacements do not yet work)
* Start vignette

The create_LIC_project.R file containing the code to copy the files and adjust the company name is still WIP.

For deferred contracts, by default the premium refund only applies during the deferral period, for all other contracts during the whole contract. This can be overwritten with the premiumRefundPeriod parameter (implemented as a function premiumRefundPeriod.default).

Fixes #86

* Add an R6 class PVfactory that encapsulated Present Value-calculation in arbitrary dimensions (the older calculatePV* functions were hardcoded to a one-dimensional vector!)
* Use the PVfactory instead of calculatePV* functions
* Convert cost PV to use the multi-dimensional PVfactory code
* Implement costs relative to benefits

Implements #80

* Fix sumInsured calcualtion from given premium
* unittest for addExtension with different tariff
* Fix policyPeriod for main contract with multiple blocks (e.g. addExtension)
* Clean up unit tests

Implement contract$addExtension to add a contract extension after maturity (both premium-free and with regular premiums)

* Allow premiumPeriod=0, indicating no premiums are paid (so an initial capital must be given)
* Fix aggregating values of child-blocks that go beyond the main contract's duration
* move sumInsured calculation to its own function for cleaner premium calculation. That function will be called earlier, so the CF data frames already use the correct sumInsured
* The additional_capital cash flow is no longer relative to the sumInsured, but gives the absolute capital

* Add parameter premium, which defines the prescribe premium (either written, written_beforetax or gross)
* The sumInsured will be derived from the premium by reversing the formulas (as far as possible)
* If both sumInsured and premium are given, the premium is ignored and sumInsured takes precedence
* The function calculatePremiums now also returns the sumInsured (in addition to the premiums and the coefficients for the premium calculation)

Implements #49, documents #63

Improve calculating the survival PV from applying recursion to each columnt to one recursion over the whole data.frame

InsuranceTarif: When the contract is cut due to reaching the end of the life table, allow one final payment AFTER the end of the life table (if q_omega < 1).

* Check whether we have any values!=0, otherwise don't calculate at all
* Add internal method calculatePVSurvival2D to allow PV calculation on a data.frame of cash-flows rather than a one-dimensional vector.

If we pad from the beginning, allow arbitrary padding values. The default 0 forces the vector to a numeric vector, so overriding is required e.g. to pad date vectors.

Also remove duplicate definition of padArray and sumPaddedArrays (already moved to HelperFunctions.R, so no need to duplicate inside InsuranceContract).

During the deferral period, no payments are made, but formally the sum insured still applies to that period (relevant for costs that apply to the SI).

Annuities: For lifelong annuities, implement survival payment at the end of the final year of the lift table (only relevant if final qx<0).