allow optional static linking

- add cmake option `CMAKE_LINK_STATIC`
- add missing `CMAKE_C_FLAGS`
- change documentation

extend `README.txt`

Topic feature complete build

add overview about advanced compile options

- throw an error if a compile dependancy is not fullfilled
- add options to disable hard compile dependancies

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.