abstract out the projection from ProjectedCostFunction and add a ProjectedConstraint class
allow for calibration of a subset of the model's parameters
add a calibration constraint which fixes the mean reversion during calibration
add a calibration constraint which fixes the first component of the piecewise volatility,
overwrite the calibrate method to make this constraint the default
add a test case for calibration with fixed reversion parameter
amend the test case for the calibration to a secondary instrument set
fix include paths
replace tabs by spaces
rename parameter
Some nitpicking on parameter names.
Extracted calibration constraint from struct.

This gives some uniformity to this kind of methods (not entirely,
though: some are static and some have to be instance methods).
Returned bare vectors instead of disposables.

It's not called in any loop, and we can rely on NRVO anyway for
copy elision.
Added new files to VC++ and Dev-C++ projects.
Merge pull request #48.

Allow for calibration of a subset of a model's parameters.