set UTF-8 for android update command explicitly

Fix for fail in to update android package. It is happened to meet under the following conditions both.

* User environment is not used UTF-8 in default file.encoding in java
* Android-sdk license text is included not-ASCII code characters.

If user define JAVA_TOOL_OPTIONS in env, inherit it.
Merge pull request #155 from attakei/patches/lock_java_file_encoding

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