Converted imports to relative paths

First off - wow a lot of changes in the 0.4 release. Upgrading was a bit painful, but the overall flow and organization is much improved - nice work. 

Now for the pull request - I use your utils as a submodule for my HW wallet auditor, and the non-relative paths were tripping me up. I touched those up and all is well. Not sure if it will negatively impact anything on your end, let me know.