- fix unique constraints on CustomerDiskSpaceOption and
CustomerUserDatabaseOption to allow multiple options from the same template
for hosting packages
- fix disk space calculation in CustomerHostingPackage
- implement hostingpackages forms AddDiskspaceOptionForm, AddMailboxOptionForm,
AddUserDatabaseOptionForm
- implement hostingpackages.views.AddHostingOption
- add new URL pattern add_hosting_option to hostingpackages.urls
- add template hostingpackages/add_hosting_option.html
- link items on hostingpackages/customerhostingpackage_option_choices.html to
add_hosting_option
