Add missing gui styles when installing

[PositroniumJS]

What are the issues this pull addresses (issue numbers / links)?

Fix #1006

Did you add tests to cover your changes (yes/no)?

No need

Did you update the documentation accordingly (yes/no)?

No need

Did you read the CONTRIBUTING document (yes/no)?

Yes

Summary

Add missing gui styles when installing with pip and fix some typos

Details and comments

Add missing gui styles when installing with pip and fix some typos

[CLAassistant]

All committers have signed the CLA.

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}

[zlatko-minev]

Have you checked this runs ok in practice? No errors

[PositroniumJS]

Have you checked this runs ok in practice? No errors

Yes, in the installed package folder you get a styles directory containing for each style the file style.qss and the directory rc with all its photos

[zlatko-minev]

Wonderful job, thank you. This all looks pretty good to me

[zlatko-minev]

Can you take a look at #1002 , this will be a major update. I will try to merge these changes into that. I want to make sure that #1002 works for you. I hope to merge it in the next week or two.