[change:minor) Renamed bisection_find into bsearch_find
(bug-fix:minor) Wrong value for upper limit index
(new:minor) Improved doc for bsearch_find method
(new:minor) Added test suite for interpolation core functionalities.
(change:minor) Renamed test case for cubic splines
(bug-fix:major) Solved some memory leaks.

(new:minor) Improved docs
(bug-fix:major) Fixed bracketing logic:
- Given n points, bracketing returns an index k such that 0 <= k <= n-2
- Removed experimental bracketing code from Numerical Recipes 3rd Ed, since it is buggy
- Use a simple binary search
(change:minor) Removed old code and added precondition check inside c'tor
(change:minor) Removed old code and added precondition check inside c'tor
(change:minor) Removed old code and added precondition check inside c'tor
(change:minor) Replace DEBUG output messages with TEST output messages.
(bug-fix:minor) Fixed test suite for interpolation core functionalities
(new:minor) Added test suite for constant and nearest-neighbor interpolation