Bug 961712 - Buffer (f)printf_stderr on Android. r=gal

Android logging functions append newlines to all output. Layout debugging
(and perhaps other areas) relies on being able to print partial lines, making
its output almost unreadable. This change adds manual buffering between
newlines, making the output readable again.
Bug 938904 - [e10s] Make tooltips work (r=smaug,enn)