version bump 3.0.6

so we can go on with new django_appdata
CachedForeignKey for listing.publishable
Positions are now always cached, even if does not exist
I don't like you, travis, it works on my machine
New PIL does not seem to seek(0) after format checking
'DateTimeField' imported but unused core/newman_admin
remove imported but unused on core/newman_admin
remove imported but unused on core/templatetags/authors
remove local variable e is assigned to but never used on core/templatetags/core.py
"pprint" imported but unused on ella/photos/management/commands/check_photo_files_consistence
"CommandError" imported but unused on ella/photos/management/commands/check_photo_files_consistence
If not import celery not run task
fix pep8 on api init: W391 blank line at end of file
fix pep8 on api middleware: E302 expected 2 blank lines, found 1
fix pep8 api serialize: E302 expected 2 blank lines, found 1
Fix pep8 api serializers: E302 expected 2 blank lines, found 1
Fix pep8 on Articles models: E303 too many blank lines
Fix pep8 on articles new man admin: E302 expected 2 blank lines
ella package: E302 expected 2 blank lines
Switching to pillow for easier installation. Thanks @avelino!