Put "Hello, world" text in a string resource
Use Holo theme with tabs
Add editorconfig
Fix editorconfig to use indent_size

tab_width specifies the displayed width of a tab character, but its
default value is set by indent_size which changes the size of a soft-tab
as well.
Cleanup gitignore
Consolidate to a single BUCK file
Use qualified class name in manifest

This makes `buck install --run` work properly.