added some utility functions for module/exec path query
refactored plugins and kernels directory lookup
use different function to check if we're unwinding the stack
allow node tree iterators to work on const NodeTree instance
added json11 library
refactored string_format function to try to use stack at first try
changed functions arg to take by ref instead of shared_ptr const ref
refactored NodeTree serializer to use json11 library and throw exceptions instead of qt log utilities
added nested exception definition for ms visual compiler
fixed warnings/errors with linux/gcc build