Fix compilation errors on 64-bit *nix

I'm not sure if the errors were caused by 64-bit arch,
using *nix, or both. But it works now.
Massive GUI cleanup; begin removing all fixed coordinates

The goal is to make the layout adapt to window resizing by
repositioning widgets accordingly, based on alignment and
anchors.
Continue fixing GUI layout
Completed GUI layout restructuring
Added README
Merge pull request #4 from thekalio/master

Restructured GUI to make widgets scale as window is resized; added README