move to newer travis infra and include flake8
move to newer travis infra and include flake8

The tests now run on Travis-CI's newer, faster containerized
infrastructure. Got rid of sudo statements in travis config in order
to make this work.

inclusion of flake8 shall hopefully ensure pep8 compatibility.

nerandell/vyked,amanwriter/vyked,kashifrazzaqui/vyked,nerandell/vyked,kashifrazzaqui/vyked,1mgOfficial/vyked