Inspection for files inside the main package that are in root folder

[mtoader]

This is needed for proper execution of the go build based setup / installation

Refs #161

[dlsniper]

I'm not sure what this means but I think it can be closed? Thanks.

[mtoader]

I'll leave it like this because it's not clear how we should handle files in package xxx which are alongside files from package yyy in the same folder.

[dlsniper]

This is still an issue as we don't have an inspection to check if files from different packages are in the same folder.