[NB] Rewrite all imports to support microdrop a...

Rewrite all imports to support installing `microdrop` as a Python
package.  Then, the `MicroDrop` app can be launched as follows:

    python -m microdrop.microdrop
Add missing plugin interfaces file.
Update `setup.py` to install as Python package
Remove submodules, install packages as dependen...

Remove submodules.  Instead, install packages as dependencies.
Replace all references to removed submodules...

Replace each reference to a removed submodule with a reference to the
corresponding external Python package.
Add auto git-describe version for Python packag...

Add automatic Python package versioning using `git-describe` through the
`version.py` module from [here][1].

A Python package source distribution can be built using the following
command:

    python setup.py sdist

__NB__ The version strings generated by `version.getVersion()` conform
to [PEP386][2].

[1]: https://gist.github.com/mina86/8782771
[2]: http://www.python.org/dev/peps/pep-0386
Add requirements files.
Remove old build scripts, only build docs.
Add install dependencies in `setup.py`.
Add packages to requirements, replace submodules
Remove dependency_links...

Remove `dependency_links` since they cause issues with recent versions
of `pip`, which require the specification of [`allow-external` and
`allow-unverified`][1] for install to work properly for this package.
In an effort to simplify things for the time-being, we simply list the
dependencies and assume that they are installed, or available through
PyPi.

[1]: https://github.com/pypa/pip/issues/1423
Remove deprecated file.
Revise docs in DmfDeviceController.save_dmf_device
Fix #133.  Update device name on save-as/rename

Update device name when performing `Device > Save As` or `Device >
Rename`.  Note that the prior to this commit, the underlying device was
actually being updated in both the `Save As` and `Rename` scenarios, but
the name change was simply not being reflected in the GUI.
Merge branch 'as_python_package' into dev
Handle plugins with from the dev branch

Update the requirements.txt to point to a new version of the
`microdrop_utility` package.

See #147
Add microdrop.__main__.py file

This allows the application to be launched in one of 3
equivalent ways:

{{{
1. python -m microdrop.microdrop
2. python microdrop
3. python microdrop/__main__.py
}}}

See #134
Move git repos to wheeler-microfluidics account
Merge branch 'ticket_133' into dev
Add script to generate Markdown latest URLs page

Usage:

    python -m microdrop.bin.latest_versions

To generate HTML page:

    python -m microdrop.bin.latest_versions | markdown > index.html

See #148.