Customizable interpolation methods to minimize the number of data points

[raylv17]

Two major modifications:

• two-step interpolation (Taking the average first, then applying the gradient (first order difference)) with user given tolerances
• Dividing the dataset: so interpolation methods can be applied with different tolerance values on different parts of the plot.

[raylv17]

Code clean up with additional functionalities:

• Ability to divide the dataset
• User inputs at the start of the code
• Added description in README.md
• Organized result/output files.