[Android] Support using intent to launch url in core shell

It's inefficient for developers to type complex urls in core
shell for debugging and testing.
Add a broadcast receiver in core shell activity to receive
intent to launch url.
Developers can use adb to send the intent like:
adb shell am broadcast -a org.xwalk.core.xwview.shell.launch -e url <url>
Merge pull request #1483 from wang16/intent_launch_url

[Android] Support using intent to launch url in core shell
[Android] Fix packaging tool can't work on python3.0+.

1. Change print to print function.
2. Change "except" expression for try..catch
3. Add decode("utf-8") for output of subprocess
4. Change "filter" and "file" uncompatible usage.
5. Move ant.py and md5_check.py into xwalk, which request modification.

BUG=https://crosswalk-project.org/jira/browse/XWALK-766