Add basic concatenation of colormaps
Clean up colormaps module
Add level as attribute of current_data

Not having level already added to current_data seemed to be breaking
things in 1d.  Line 421 caused this:
```
current_data.level = getattr(patch,'level',1)
```
Add example of usage
Merge pull request #105 from mandli/fix-current-data-level-bug

Add level as attribute of current_data
Add ability to plot only selective gauge locations
Ensure that mapc2p is applied to coordinates just once.
Merge pull request #108 from ketch/apply_mapping_only_once

Ensure that mapc2p is applied to coordinates just once.
Avoid applying mapping to later plots when not requested.
Merge pull request #109 from ketch/apply_mapping_only_once

Avoid applying mapping to later plots when not requested.
Merge pull request #107 from mandli/fix-gauge-select-location-plotting

Add ability to plot only selective gauge locations
Works for me.
Fix example for add_colormaps
Add more user friendly interface to adding colormaps

This now takes care of the data range and break location mapping from
data space to the colormap space.
Merge pull request #102 from mandli/add-colormaps

Add basic concatenation of colormaps