Remove unused imports.
Whitespace.
Add a test for special (dunder) unary operations.

Currently fails for `abs`.
Fix distarray `__abs__`.
Add failing test for localarray abs.
Fix localarray abs.
Merge pull request #562 from enthought/bugfix/abs

Fix `abs` for DistArrays and LocalArrays
Merge pull request #560 from enthought/feature/rearrange-examples

Rearrange examples
Merge branch 'master' into feature/improve-examples
Fix benchmark_julia.