Overlay.uc.xul: minor fix: fix typo in commit: 3b0312c
create common function |scanPlacesDB|
UI: check URL visited and bookmarked with querying Places DB

* avoid using nsIURI so that fix some problems:
* fix the character escaping problem
  see https://bugzilla.mozilla.org/show_bug.cgi?id=817374
* can get the visited time of a redirected URL
UI: avoid redundant calling |setOverLink|
URLBarTooltip: fix useless separator