Assign a type to get_guide_catalog cats to plot

[jeanconn]

Assign a type to get_guide_catalog cats to plot.

Closes #260

[jeanconn]

If we are sparking some joy, can I have this bug fix to plot guide catalogs? I have not added a test.

[taldcroft]

Just need a functional test (you doing something in ipython or whatever) to verify this is working, and passing unit tests.

[jeanconn]

Right, I had basically done:

fido: ipython
Python 3.6.2 |Continuum Analytics, Inc.| (default, Jul 20 2017, 13:51:32) 
Type 'copyright', 'credits' or 'license' for more information
IPython 6.1.0 -- An enhanced Interactive Python. Type '?' for help.

In [1]: from proseco.acq import get_acq_catalog

In [2]: from proseco.guide import get_guide_catalog

In [3]: from proseco import get_aca_catalog

In [4]: %pylab
Using matplotlib backend: TkAgg
Populating the interactive namespace from numpy and matplotlib

In [5]: acqs = get_acq_catalog(20603)

In [6]: acqs.plot()
Out[6]: <matplotlib.figure.Figure at 0x7f93c958da58>

In [7]: guides = get_guide_catalog(22058)

In [8]: guides.plot()
Out[8]: <matplotlib.figure.Figure at 0x7f93c8b8d400>

In [9]: cat = get_aca_catalog(21872)

In [10]: cat.plot()
Out[10]: <matplotlib.figure.Figure at 0x7f93b4b8c470>

And confirmed plots were made. Unit tests (which also have some plot calls) were still passing.