add helper functions to make examples more readable

[hholzgra]

right now all examples have the full initialization and connect code in their respective source files, this makes finding the actual example code for the function at had hard for the casual reader

[hholzgra]

Helper functions helper_connect() and helper_end() have been added in new include file helpers.h

[hholzgra]

a few first examples have been converted to use the helpers to make them much more readable, but this is is still work in progress ...