Small Minor Bugs

[HKaras]

Here is a collection of small bugs in need of fixing.

• Remove the default font in the plot function. The Calibri font is a propriatary font of Microsoft and is not always avaliable leading to error messages.
• Missing figures in modeling_guide.html
• In the test test_algorithms the optimal regualrisation exists outside the search bounds.

[HKaras]

Aditionally:

• The crossing echo example is broken
• There is a typo in fitting_guide