Added the pip requirements file

This installs third party requirements present in the Python Package
Index using the following command:

    pip install -r requirements.txt
Fixed the CGI she-bang line to be more portable
Revert "Added the pip requirements file"

This has been reverted because the `python-epsg` module fails to
install due to it not being able to find the `sqlalchemy` module.
Installing the requirements separately, however, works.

This reverts commit 16cc66838c07357dcf4a8147742154305aca55fd.
Added Dockerfiles for generating Portal deployment docker images
Removed `python-epsg` and `python-skos` as git submodules

These can now be installed from the Python Package Index using PIP
e.g:

    pip install python-epsg==0.1.3 python-skos==0.0.3
Fix the base Dockerfile to update from the correct package repository
Set the correct permissions in the base image temporary directory
Set the correct base image for the mod wsgi docker image
Correct the `/tmp` directory permissions in the docker images
Remove custom Apache log files from the docker images
Removed redundant links to `epsg` and `skos` modules
Upgrade to use Mapnik v2.0 for the metadata images
Enable the localhost port of the web server to be configured

This represents the port that the webserver is running on when
accessed from localhost.  This is used in the GDAL data source used to
access the tile mapping service through a self-referencing URL. It
needs to be set if port forwarding is used to expose the application
to an external web server on a non-standard port, which otherwise
results in an invalid `SERVER_PORT` server variable (the forwarded
port is used, rather than the actual local port).
Fix the file path to the GDAL WMS data source file from the VRT

This is used in generating the background layers in the metadata
extent images.
Document the docker support
Fix links and add more docker specific documentation
Hard link the data directory when building the base docker image

The data directory has to be hard linked rather than symlinked so that
relative links within `data/raster/background-wms.vrt` work correctly.
Upgrade to `python-epsg` 0.1.4

This works around a problem with the EPSG Registry API export
functionality.
Update the EPSG registry cache when building the base image
Add documentation links to the Docker Index