[sailfish-browser] Virtualize background tabs upon lowmem signal
[sailfish-browser] Avoid unneeded loop if there is only one live page
[sailfish-browser] Don't virtualize pages with parent-child relations
[sailfish-browser] Run gc upon lowmem if browser is backgrounded for 10min
[sailfish-browser] Don't assume there is a live page always
[sailfish-browser] fix identation
Merge pull request #222 from rojkov/lowmem

[sailfish-browser] Virtualize background tabs upon lowmem signal