ENH: Make plot_displacements more flexible; change default arrow appearance.
RLS: Version 0.2.1
Merge pull request #120 from danielballan/rls-0.2.1

RLS: Version 0.2.1
DOC/BLD: Fix setup.py for ReadTheDocs.
Merge pull request #121 from danielballan/fix-readthedocs

Fix readthedocs
DOC: Update README with scikit-image, pip installation.
DOC: Add reminder to update version string in docs
DOC: Made beginner instructions gentler
Merge pull request #125 from nkeim/update-sphinx-version

DOC: Add reminder to update version string in docs
Merge pull request #123 from soft-matter/readme-update

DOC: Update README with scikit-image, pip installation.
TST: Refactor image position xy handling.
Merge pull request #105 from danielballan/arrows

ENH: Make plot_displacements more flexible; change default arrow appearance.

This should really be done with quiver, but is very annoying to get the arrows to look good.
TST: Add simple 3D tests.
Merge pull request #129 from danielballan/test-3d

Test 3D feature-finding
CLN: Remove stray MANIFEST file.
Merge pull request #130 from danielballan/remove-manifest

CLN: Remove stray MANIFEST file.
FIX: in plots, annotate, fixed error in how we check for thresholds being iterable
TST: Add tests for annotate.
Merge pull request #134 from danielballan/plot-tests

FIX/TST: Fix typo in annotate, add many tests.
REF: Support Python 3 using six.