general improvements and fixed CK web service vulnerability

• fixing detection of CK installation even when ck is soft linked
• changing remote-ck repo URL pointing to cknowledge.org/repo (after moving personal CK server to Azure cloud)
• adding support for basic http authentication for remote repositories
• adding automatic recaching of repositories if has remote access ...
• adding support to automatically open web service and browser via "ck browser" (or "ck browser --template={template}" with a given web template) similar to ipython notebook
• adding possibility to open a given entry in a browser via "ck browser test:unicode" or browse entries via "ck browser dataset:" ...
• fixing CK server vulnerability (action with ; can run various CMD commands)
• fixing above vulnerability both in php and python ...