Merge pull request #237 from knowledgepoint-devs/modal

Fixed text value for submit button on ask form, added __unicode__ methods for AuthUserGroups and GroupMembership models, plus more improvements to admin site.
Merge pull request #239 from knowledgepoint-devs/modal

Improvements to admin list view for Tag model.
input validation bugfix in the convert comment to answer
Merge branch 'modal' of github.com:ASKBOT/askbot-devel into modal
Merge pull request #243 from knowledgepoint-devs/modal

User/Person admin list view: add email_tag_filter_strategy and allow filtering by that and display_tag_filter_strategy
fixed an issue with email alerts when there are no tags in the alert subject line