Finished task 8:
- Fix of online estimator computation.
- Implemented test for identity of the two estimator implementations.
Added C++11 implementation of the standard normal distribution to task 2
files.
Added variance estimator function for printing convergence plot data
into an output stream.
Added include guards to "estimator.h".
Merge branch 'master' of https://github.com/ChaseN7/NumerikPraktikum14.git
Task 9:
Added function to generate data for convergence plots for the variance
estimator.

Some minor fixes.