Reorder dependency docs and correct windows part

[pfaion]

The Windows section contained outdated links to the old Pupil docs. I copied over the necessary text, so we don't need to link to the Pupil docs anymore.

Additionally, the dependency install instructions came AFTER the install instructions, which normally does not make much sense. So I reordered them.

[willpatera]

@pfaion are there macos setup dependencies included? I would say merge this, but would like to add any macos specific instructions - @papr do you want to contribute these?

[pfaion]

@willpatera good point about the macOS dependencies. @papr looks like you can just install GLFW 3.3 from brew. Can you confirm that this would work for PI Monitor? I can just add a small section with brew install glfw for macOS dependencies.

[papr]

@pfaion As it turns out, pyglfw comes with its own glfw library. Therefore, we can remove the requirements to install glfw via brew

[pfaion]

Looks like we should check again if we need any libglfw then. It looks like the pyglfw package also ships glfw shared libs for Windows and Linux. I'll try this for Windows and Linux and check if we need libglfw at all.

[pfaion]

Note: there's even more to fix! The default script installs pyglui from source, which does not work on Windows. Here we have to install the wheel. Will have to rework the workflow with the requirements.txt.

@papr what was the reason for all of these being editable installs? -> https://github.com/pupil-labs/pupil-invisible-monitor/blob/9324d412f52f82b10fdbd16fca40dbb9615b958c/requirements_custom.txt

[pfaion]

The same ☝️ holds for pyNDSI btw.

[papr]

Editable installs are the only way to add custom dependency urls to your requirements that I know of.

[pfaion]

Closed in favor of #22 which is a lot cleaner.