#583 Gentrified IChemObject getProperty

[John May]

Made the getProperty method of IChemObject generic so we don't have to do casts when calling. https://github.com/johnmay/cdk/tree/master+

currently

Integer number = (Integer) atom.getProperty("number");

now

Integer number = atom.getProperty("number");

I also made one which can be chained

String hex = atom.getProperty("number", Integer.class).toHexString();

This does not change any existing using code as they are effectively calling the return type of Object which is then cast if needed.

[Egon Willighagen]

This is cool stuff!

[Egon Willighagen]

Applied and pushed.