add overview about advanced compile options

refactor CMake

- allow compiling without microhttpd
- allow compiling without OpenSSL
- install `config.txt` with command `make install`

Simplified expression

webdesign - little tweaks for better looks

* Update webdesign.cpp

* Update webdesign.cpp

Update README.md

I thought it might be best to add a few more dependencies to the example script as these do not come installed by default. Also added a link to the AMD GPU version.