Example Configuration for K8200 : comments/URL/readme

example_configurations\K8200\Configuration.h:
* add machine specific header
* change STRING_URL to K8200 fork (@thinkyhead: What do you think?)

example_configurations\K8200\readme.md:
* updated documentation
* added URLs and links

* readme.md: updated typo and URLs

Example Configurations for K8200 readme.md updated
* readme.md: added description for german umlaut support on LCD

# Add: Example Configuration for Vellemann K8200 - based on new
BOARD_K8200 #1391

* K8200: new folder in example_configurations for Vellemann K8200 (3Drag
clone - should work with 3Drag http://reprap.org/wiki/3drag, too. Please
report)
* K8200/Configuration.h/Configuration_adv.h: updated manually with
parameters form genuine Vellemann Firmware "firmware_k8200_marlinv2"
based on the recent development branch

I tested the changes on my K8200 with 20x4-LCD and Arduino 1.0.5 for
Windows (SD library added to IDE manually) - everything works well