Added django admin style registration (for now)

Big changes to how things are structured, ModelAdmin2 handles its views and urls
Reformat modeladmin urls
add Andrew Ingram to contributors
Merge pull request #47 from ludw/master

Fixed spelling in contributers
Adding Travis-CI configuration file.
Add the travis-ci green/red badge to the readme file.
Add missing newlines at end of files
Merge pull request #48 from AndrewIngram/registry

Registry
Adding Gregor Müllegger to the CONTRIBUTORS file.
merge
Merge pull request #49 from gregmuellegger/travis-ci

Implementing Travis CI integration.
merge
Refactor views to use new Admin2Mixin
Fixing setup.py if django is not installed.

djadmin2 must not be imported in setup.py because this triggers an import of
django and other dependencies which will obviously fail if they are not
installed.
Fix incorrect template being extended.
Merge branch 'issue44' of git://github.com/inglesp/django-admin2 into inglesp-issue44
Merge pull request #52 from audreyr/template-fixes

Fix incorrect templates being extended.
Merge pull request #53 from gregmuellegger/setuppy-fix

Fixing setup.py if django is not installed.
runtests.py can now be executed directly