Feature for custom fonts

Include tests in swiftlint check and fix violations

and fix violations.

Update CI settings

Update .travis.yml

It looks like the `id` of the simulator device I was using changed, updating the ID should fix it.

Update swift version

Silence swiftlint warning and update rules

Added an of(size:) method to the Font enum.

Add Cocoapods download count badge to README.md

Raise version in podspec to 0.1.1

Introduce Swiftlint and correct errors