Some docs for compiling

[mehmetkose]

trafficstars

It's good to watch this how to go forward. Thanks!

I don't need desktop notifications or electron like API's. I just wanna build a preview desktop for my website. Can you add more docs for compiling, please?

I understand this is alpha now and things can be changed at any time. But I want to give it a shot!

[branchseer]

I just updated the Building Instructions. Let me know if you encounter any problem!

[tiptronic]

Building the Mac-version looks good. But I have some questions about the Windows-version:

• do we need npm / nodejs installed on Windows to build the binary? A couple of more granular info on the requirements would be very helpful.