Merge pull request #1 from landlab/master

merging
Added _make_link_unit_vectors() to grid base.py

This method, which is meant to be called on initialization,
calculates and stores unit vectors associated with each
link.
Grid: link unit vectors, part 1

Added _make_link_unit_vectors to grid.base, and call to
it in grid.raster.initialize. Next, need to implement special
raster version, and also call base version from
grid.voronoi.initialize
Added a testing section to the developer guide.
Merge pull request #42 from mcflugen/add-testing-docs

Added a testing section to the developer guide.
Fixed issue #33.

Fixed
-----
* Updated the installation instructions to only list the recommended
  ways of installing landlab. For Windows and Mac this is from GitHub
  with the GitHub GUI, for Linux it's from the command line with git.
Fixed issue #33.

Fixed
-----
* Updated the installation instructions to only list the recommended
  ways of installing landlab. For Windows and Mac this is from GitHub
  with the GitHub GUI, for Linux it's from the command line with git.
Merge branch 'fix-issue-33' of github.com:mcflugen/landlab into fix-issue-33
Merge pull request #43 from mcflugen/fix-issue-33

This fixes issue #33.
Delete test-results.xml

This is a temporary file generated by `nose` and so doesn't need to be in the repository.
Delete dev_guide.rst~

This is a temporary file generated by vim/emacs and so shouldn't be in the repository.
Delete install.rst~
Added vim temp files to list of ignored files.
_make_link_unit_vectors in grid base and raster

Completed _make_link_unit_vectors() methods in
grid.base and grid.raster, with doctests, and calls from
RasterModelGrid and VoronoiDelaunayGrid constructors.
Minor edits to model_grid.rst
major updates to the overland flow component

Updated overland flow component to reflect the changes I made pre-CSDMS.
Still a work in progress!
Added coveralls to .travis.yml.
Updating slope-aspect raster grid routines

Added a new, faster (? - not looped) method to find the local slope and
aspect of a core node in the grid. This should now play nicely with
grids with boundary nodes that aren’t perimeter nodes.
Also, updated diagonal_lists and neighbor_lists so they’re now
internally consistent: both now use BAD_INDEX_VALUE, and boundary nodes
can now have neighbours, as long as they’re core nodes.
Work on link-to-node mapping

Implemented map_link_vector_to_nodes. It "works" but
there seems to be a problem with the underlying math.
Added fn to grid.base.py for vector projection

Function is find_true_vector_from_link_vector_pair(). Part of new code
for mapping link vector data onto nodes, broken into vector (x,y)
components. That way, we can output this and make vector plots.