Add utils::Configuration
Use googletest

I waited until I had components, that I could actually test
Improve utils::Configuration

Check wether file exists before reading
Make all the get_type methods simpler
Add save ()
Add ConfigurationTest.CreatingNewValues
Change utils::Configuration

It is now possible to acess, modify and add elements within the elements
Split utils::Configuration and utils::Configuration_element
Add utils::Configuration_list_element

Add some more tests as well
get_element and get_list_elemnt now return shared_ptr
Merge branch 'configuration'