v0.7.6

This is a minor release that significantly simplifies basic arithmetic and logical operations.

Simple methods such as +, - etc. can now use standard python syntax.

For example, if you wanted to add 2 to a dataset you can now do the following:

ds.add(2)

as this instead

ds+2

The same goes for logical operators. You can do the following to identify if the values in a datset are below 2:

ds<2

whereas you previously had to do this:

`ds.compare("<2")

Note: because nctoolkit methods only modify datasets and do not return datasets, the following will not work:

ds1+ds2+2

Instead, you would need to do:

ds1+ds2
ds1+2