Remove a number of unused Python scripts
Remove a number of unused Python scripts

Removes sky_tool and shelldb, which are replaced by the flutter command line
tool.

jason-simmons/flutter,Hixie/flutter,flutter/flutter,aghassemi/flutter,jason-simmons/flutter,tvolkert/flutter,jason-simmons/flutter,tvolkert/flutter,flutter/flutter,Hixie/flutter,cbracken/flutter,aghassemi/flutter,turnidge/flutter,turnidge/flutter,flutter/flutter,tvolkert/flutter,tvolkert/flutter,Hixie/flutter,flutter/flutter,tvolkert/flutter,Hixie/flutter,turnidge/flutter,Hixie/flutter,tvolkert/flutter,cbracken/flutter,tvolkert/flutter,Hixie/flutter,cbracken/flutter,turnidge/flutter,Hixie/flutter,cbracken/flutter,tvolkert/flutter,Hixie/flutter,cbracken/flutter,tvolkert/flutter,Hixie/flutter,cbracken/flutter,cbracken/flutter,flutter/flutter,flutter/flutter,aghassemi/flutter,tvolkert/flutter,aghassemi/flutter,turnidge/flutter,Hixie/flutter,jason-simmons/flutter,cbracken/flutter,flutter/flutter,flutter/flutter,cbracken/flutter,cbracken/flutter,flutter/flutter,flutter/flutter