v0.11.0: Don't use SymPDE's obsolete classes Scalar/VectorField (#9)

* Do not import obsolete classes ScalarField and VectorField from SymPDE - they were not used anyway;
* Update version.

v0.10.0

Update version.py (#8)

v0.9.4: Clean up installation procedure with pip (#4)

* Move dependencies list from 'requirements.txt' to 'setup.py'.

* Move library version to separate file.

NOTE: gelato now provides version to user:

In [1]: import gelato; gelato.__version__
Out[1]: '0.9.3'

* Enable tests with Python-3.7.

* Update __version__