set "UTF-8" to java file.encoding for android update command explicitly



Hi.

In current version Bulldozer, I have failed to run command "buildozer android debug".
I examined from output exception, and found the next thing.
* Current(2014/10/25) Android-sdk license is included Non-ASCII characters.
* There is an environment that is not used UTF-8 to default file.encoding for java (ex: Mac OS in Japanese).
* In this environment, Android command do output license as Non-UTF8. And Then, Buildozer fail to output characters and raise exception "UnicodeDecodeError".

So I try to fix it.

attakei