Utilize new Python features available from dropping 2.7 and 3.4

[tobinus]

Depends on #96 and #97 .

Basically, there are a lot of simplifications that can be made by utilizing Python features/changes that previously could not be used due to supporting legacy Python versions. I want to reap the benefits of dropping support for 2.7 and 3.4 because:

• It will lead to a better experience for developers, which is important to ensure continued support.
• Dropping support for 2.7 and 3.4 would be pointless if it did not improve anything.