Merge pull request #110 from slayoo/master

TODO update
strang -> trapez
Merge pull request #111 from slayoo/master

strang -> trapez
small changes in resoultion of analytical fig
Merge pull request #112 from djarecka/master

small changes in resoultion of analytical fig
changing color of analitical solution
Merge pull request #113 from djarecka/master

changing color of analitical solution
code to plot a  2D droplet surface
changes in resolution of analytical solution
adding calling the plot2D_shallow_water_2d.py
Merge pull request #114 from djarecka/master

adding code to plot a 2Ddroplet surface
sync with changes in spreading_drop