Notifications: Prevents SectionFooter from rendering
NoteTableHeaderView: Updates Style
NoteTableHeaderView: Fixes incorrect height assignment
NoteTableHeaderView: Implements custom separator
NoteTableHeaderView: Updates Style. Part II
NoteTableHeaderView: Updates Style. Part III
Merge pull request #2540 from wordpress-mobile/issue/2502-fixes-unwanted-horizontal-lines-in-notifications

Fixes unwanted horizontal lines in Notifications