Scorer is not very good for matching on filenames

[octref]

• VSCode Version: 1.5.2
• OS Version: OS X 10.11.6

The repo is Microsoft/vscode.

[bpasero]

This is actually a corner case where our scoring is bad: Parts of the filename (explorerview.ts) end up matching on the folder instead of the file name. It is just bad luck that in this case explorerView.ts has parent folders that match more on the query compared to explorerViewModel.ts.

Overall we need to revisit our scoring functions and improve it to work better with files.

[bpasero]

Fixed via 9d40f0c