gs_data/ghec_viewer/features:

Added ghec viewer feature/layer.
fabfile:

Added ghec viewer app.
gs_data/ghec_viewer/styles:

Added/moved style SLD for ghec_viewer.
gs_data/ghec_viewer/styles:

Added ghec_viewer style files.
gs_data/ghec_viewer/layers:

Added ghec_viewer layer.
gs_data/ghec_viewer/styles:

Removed an obsolete style file.
gs_data/ghec_viewer:

Fixed up layer and style data.
fabfile:

Added `_geoserver_api_from_file` and made the geoserver api utils
a little more useful.
fabfile:

Cleaned up geoserver api calls and added status messages.
fabfile:

Fixed the ghec_viewer geoserver styles. Before, it was totally wrong.
fabfile:

Broke the bootstrap function into a couple of smaller composable
functions.
README.rst:

Added submodule notes to the dev env setup instructions.
Merge pull request #72 from larsbutler/ghec-devenv

Dev bootstrap script: ghec_viewer (styles, etc.)

[r=nastasi-oq] [f=1221929]