Use regex for content search to fix "string not found" bug + email backup command + endless pagination bug fix

(Also tidied up some of the search code)
See bug description: https://trello.com/c/cH5tW54O/105-search-bug-string-not-found

Endless pagination bug: https://trello.com/c/XkUWPrxC/184-facebook-modal-window-fix-bug-when-loading-through-endless-pagination