email contact => @fbreader.org + new background preference

Updated.
I had used an old en.xml which was obtained from http://fbreader.org/content/documentation/i18n/android
Merge pull request #222 from tamo/patch-2

email contact => @fbreader.org + new background preference
Merge branch 'master' into ice-cream-sandwich
Merge branch 'ice-cream-sandwich' into yota2
Merge branch 'yota2' into kindle