Feature/abstract rendering guides

* Adds proper axis support to abstract rendering images
* Fixes early/eager abstract_rendering import warning, closing #747.  Now only prints the warning when the server tries to instantiate the AR object.  Updated warning message to include pip and conda (as well as the AR repo)
you can replace all these prints with something like this:

```python
print("""\n\n-----------------------------------------------------------------------
Error loading the abstract_rendering package.\n
To use the ar_downsample module, you must install the abstract rendering framework.
This can be installed with conda, pip or by cloning from https://github.com/JosephCottam/AbstractRendering
Questions and feedback can be directed to Joseph Cottam (jcottam@indiana.edu)
-----------------------------------------------------------------------\n\n""")
```