delete unnecessary files from bower installs

[sigmundch]

I'd remove:

• index.html
• things from other packages that are not needed (for example in paper-elements we shouldn't have to have a copy of demo.html of a core-element).

More details here https://github.com/dart-lang/core-elements/issues/32

Not sure if this is general enough to do it automatically, or something we should configure on the config.yaml file.

[jakemac53]

I think just allowing a list of Regexp patterns over file names would be fine.

[sigmundch]

actually - for core-elements in paper-elements, we could practically delete the entire folders and just create the stubs that are already listed in the config file (and recreate the folder where they are).

Maybe we can just list the directories to wipe for this case?

[jakemac53]

The way it works now will effectively do that, you can just put the directory name and that will match all files under it. Since git doesn't actually know about folders I am just skipping them.

[sigmundch]

One thing to keep in mind though is that pub-lish might not ignore the empty dirs.

So far we actually anyways plan to keep a file on each dir, so the current solution might be exactly what we need.