Closes #18

Closes #17

Closes #15

Closes #13

Closes #12

* Shows only analysis plugins by default on /api/plugins
* Adds a plugin_type parameter to get other types of plugins
* default_plugin chosen from analysis plugins

pip install needs the VERSION file - `make version` will create that file

I also added the -U flag to pip install to force install (this is important if the user is playing with the code or trying out different older versions, as pip will not install if it thinks the git repo represents a version already installed or older than the one installed)

Installing depends on the VERSION file, so it raies an error if it is
installed in some other way.

ReadTheDocs installs the package so it can generate code docs.
This commit adds a default version 0.0

Since __init__ is imported by setup.py, future may not be installed yet.

Other options would be:

* Read VERSION -> and that code has to be duplicated in setup.py and
  senpy (to avoid the import, once again)
* Eval version.py
* Do without versioning :)

Doing docker push without a tag makes the client upload **ALL** the
images it has for that repo.

Should fix #11

* Client now raises an exception on error
* Added conversion to the documentation

* Changed the way modules are imported -> we can now use dotted
  notation (e.g. senpy.plugins.conversion.centroids)
* Refactored ekman2vad's plugin -> generic centroids
* Added some basic tests

Am I a complete moron?

* Docker all the things!
* Make all the things!
* Fixed version.sh

* Added conversion plugins (API might change!)
* Added conversion to the analysis pipeline
* Changed behaviour of --default-plugins (it adds conversion plugins regardless)
* Added emotionModel [sic] and emotionConversion models

//TODO add conversion tests
//TODO add conversion to docs

Use git to automatically fetch the version

* Added interactive debugging
* Better exception logging
* More tests for errors
* Added ONBUILD to dockerfile
  Now creating new images based on senpy's is as easy as:
  ```from senpy:<version>```. This will automatically mount the code to
  /senpy-plugins and install all dependencies
* Added /data as a VOLUME
* Added `--use-wheel` to pip install both on the image and in the
  auto-install function.
* Closes #9

Break compatibilitity:

* Removed ability to (de)activate plugins through the web