v0.3.3

Measures v0.3.3

Diff since v0.3.1

Merged pull requests:

• add methods for zero and convert on AbsoluteLength (#22) (@bjarthur)
• add continuous integration for tests (#23) (@bjarthur)
• bump patch version (#24) (@bjarthur)
• Implement a 2-arg Base.hash() instead of 1-arg (#27) (@JamesWrigley)

Closed issues:

• TagBot trigger issue (#25)
• [FR] Support relative lenghts (#26)