WX version compatibility for Gooey, Pip, Conda, and OS platforms

Placeholder for working out how best to structure Gooey’s WX dep such that installs across different package managers, platforms, and OSs can all work (mostly) seamlessly, or at least have a useful escape hatch.

Problems:

• WX’s minor versions are not stable, as such, Gooey is very conservative with its deps and locks WX to a known stable version
• The WX version Gooey uses isn’t available in package managers like Conda.
• There doesn’t appear to be a single blessed WX version which can satisfy all installation requirements (for instance, the previous 4.0.7 caused issues on Linux)

Planned Solution:

Gooey will loosen its grip on developing against a single known stable WX version, and work with a sliding window starting from 4.1.0 up to current 4.1.1 (and onward as relevant).

[chriskiehl]

Dependency version has been changed to >=4.x

[casperdcl]

FYI the conda installation was fixed for gooey>=1.0.8 https://github.com/conda-forge/gooey-feedstock/issues/6