sln version

Using VS2013, version 12
Added real level fixes #14

level.json could be minimized, but 1.txt is easy to read and rather
minimal in how much data it presents
Rendering square and bug

We now preserve the x-to-y ratio of the puzzle, which looks better.
Fixed a bug where if the puzzle data had a TL.[xy] > 0 it would not be
discovered.