[yt-dev] [yt_analysis/yt] Native gdf files fail with SlicePlot (issue #550)

[Kacper Kowalik]

New issue 550: Native gdf files fail with SlicePlot
https://bitbucket.org/yt_analysis/yt/issue/550/native-gdf-files-fail-with-sliceplot

Kacper Kowalik:

Following code:

```
#!python

from yt.mods \
    import load, SlicePlot
from yt.utilities.grid_data_format.writer \
    import write_to_gdf

pf = load('yt/tests/DD0010/moving7_0010')
write_to_gdf(pf, 'moving7_0010.gdf')
del pf

pf = load('moving7_0010.gdf')
slc = SlicePlot(pf, 'z', 'Density')
slc.save()
```

yields


```
#!bash

  File "foobar.py", line 14, in <module>
    slc = SlicePlot(pf, 'z', 'Density')
  File "/home/xarth/codes/yt/yt/visualization/plot_window.py", line 1143, in __init__
    PWViewerMPL.__init__(self, slc, bounds, origin=origin, fontsize=fontsize)
  File "/home/xarth/codes/yt/yt/visualization/plot_window.py", line 743, in __init__
    PWViewer.__init__(self, *args, **kwargs)
  File "/home/xarth/codes/yt/yt/visualization/plot_window.py", line 568, in __init__
    if setup: self._setup_plots()
  File "/home/xarth/codes/yt/yt/visualization/plot_window.py", line 877, in _setup_plots
    parser.parse(colorbar_label)
  File "/usr/lib64/python2.7/site-packages/matplotlib/mathtext.py", line 3010, in parse
    box = self._parser.parse(s, font_output, fontsize, dpi)
  File "/usr/lib64/python2.7/site-packages/matplotlib/mathtext.py", line 2344, in parse
    str(err)]))
ValueError: 
\/\/(\)
     ^
Unknown symbol: \ (at char 5), (line:1, col:6)
```