Increased version number to 1.3.1.
Backported fix from master.

Change input parameters used as return values to references; change
cached values due to the correction; disable slow test case.
some minor improvements to Makefile.am
add a (common for R packages) cleanup script to tidy src/*
Added package-cleanup file to distribution.
Merge pull request #22.
additional integrals
added UnaryFunction support to Java interfaces for root finding and
integrals
added Java example for UnaryFunction callback
changed formatting
improved formatting
improved formatting
revert version change back to 1.4
added loadLibrary call
remove cap for F (this causes violations of the C^1 property in certain cases)
require decreasing call prices for exponential extrapolation
fix floor pricing
fix error check in vanilla engine tests,
exclude 0.10 strike and change strike 0.07 to 0.06 in cap engine test,
use correct yield and volatility termstructure in cap engine test
added analytic implied bpvol
disable non working test case
Updated VC++ and Dev-C++ projects.
Merge pull request #24 from Gary Kennedy.

Added the analytic implied volatility approximation of J. Choi, K Kim
and M. Kwak (2009), “Numerical Approximation of the Implied Volatility
Under Arithmetic Brownian Motion”, Applied Math. Finance, 16(3), pp.
261-268.

Given the premium of an option, it provides an analytic approximation of
implied volatility of the Bachelier formula. In interest rate the
volatility is referred to as bpvol.
Removed extraneous parameters.