Merge pull request #37 from SonOfLilit/master

- Windows notes
- indentation advice
- Square solution correction
Add requirements.txt for packages needed to build

Use "pip install -r requirements.txt" to install all
dependencies automatically
Refactor getting started page, to be more consice

about consoles and running python.
Reorganise loops infront of functions, copy-editing

Adding trailing spaces to unfinished sentences; trying
to keep lines to 80 characters.

Hopefully make language clearer for issue #25
made a sentence less confusing, as suggested by a learner in our workshop