Add code to perform k=1 experiments for location estimation, linear regression and PCA. Still debugging it.

Includes implementations of Huberized-loss versions of these (one in robust_pca.py).
Added code to perform k=1 experiments for location estimation, linear regression and PCA. Currently works, but in development and redundant.
Added code to perform k=1 experiments for location estimation, linear regression and PCA. Currently works, but in development and redundant.

- Replaced some hasty instances of "Huber" with a more precise name.
- Added an untested alternate weighted_model_find_beta3 based on our sample complexity results, to test.
- Adjusted the experimental code a bit, and the display code quite a bit.
Refactor single model finding without given beta; algorithm variant chosen by algorithm parameter sent to weighted_model function, and minor stuff.

Change order of appearance of experiments.