Empty the search keywords should empty the search results too

[Contribucious]

As in "Echofon for Mac", when clicking to empty the search keywords, the search results should be emptied too.
http://i.imgur.com/LIPsZid.png -> http://i.imgur.com/HlbCzyA.png

In fact, in Echofon (and would be good too in Birdie), even when we MANUALLY delete the keywords with backspace/delete key, precisely when the LAST character is removed, the search results disappear too. Logical and good for privacy too, to not let search results from a previous search always stay in a tab. ;-)

About the fact that, Echofon, rather than having a "blank" search results page then, have a default search page with "Saved Searches" feature is an other story. That'll be discussed in a other report as a potential new feature. ;)

TECHNICAL INFORMATION:
OS: Ubuntu 12.04.2 LTS (with Cinnamon)
Birdie version used: the r244 from the DAILY repository