added support for child themes through adding if exists for bones_ funct...

if you create wp bootstrap child themes (e.g. https://github.com/khbites/lgl-wp-bs ) you will need to adapt some of the bones_ functions in the child theme yourself.

as the child-theme functions will ALWAYS load first you need to add the "if ( ! function_exists() )" before defining functions that potentially need to be redefined.
This won't change functionality, if you do not use child themes, but makes child themes possible.