GUI: human way of setting membership expiration

 - enable change of membership expiration from member's detail page
 - pick date from date picker (set attribute) or set as never (remove attribute)
 - fixed setting attribute inside RichMember object
GUI: show shortname of ApplicationFormItem

 - on application settings page show shortnames also
 for HTMLComment and Button types of form items.
Merge pull request #90 from zlamalp/devel

Devel