Port to 1.2 template loaders

[cxallan]

As of Django 1.2 the template loaders have gone from a callables based API to a class based one. Our usage will need to be ported throughout the application. Some details are available here:

• ​https://docs.djangoproject.com/en/1.3/ref/templates/api/#template-loaders

Some of the deprecation warnings that not porting to this API create can be seen in #7118.

[wmoore]

Seems that the update to Class loaders requires us to edit 'omeroweb/settings.py'

Need to replace this:

TEMPLATE_LOADERS = (
    'django.template.loaders.filesystem.load_template_source',
    'django.template.loaders.app_directories.load_template_source',
#     'django.template.loaders.eggs.load_template_source',
)

With this (default)

('django.template.loaders.filesystem.Loader',
 'django.template.loaders.app_directories.Loader')

​http://docs.djangoproject.com/en/1.3/ref/settings/#std:setting-TEMPLATE_LOADERS

[wmoore]

It seems that it is not necessary to have an app turned "on" in order that you can use the templates within it:
​http://docs.djangoproject.com/en/1.3/ref/templates/api/#template-loaders

Although you will need to add the location to TEMPLATE_DIRS.

Your templates can go anywhere you want, as long as the directories and templates are readable by the Web server. 
They can have any extension you want, such as .html or .txt, or they can have no extension at all.

[jburel]

Referencing ticket #7116 has changed sprint.

[cxallan]

All done and working.