Adapt to Python 3
Created by: nudomarinero
The changes proposed would adapt LSMTool to work in Python 3. All the tests are passing in Python 2.7, 3.4, 3.5, and 3.6. Apart from the changes in the imports the main change is the use of Unicode strings in numpy. As this is an internal representation of the data I do not expect to cause incompatibilities with previous versions but I am not completely sure about this. This will also solve issue #4 (closed).