more notes and remove unused stdbool include
stub out initializer list function and implement free
add print function
implement bt_insert
add thoughts regarding the binary_tree opaque type
remove magic return value
factor out non-null tree insert case into private method
add whitespace for readibility
more notes on binary_tree
make parameters const for functions guaranteed not to manipulate the binary_tree reference
be explicit about binary_tree being a reference type
(e.g. opaque pointer type)
implement create with values in terms of insert
refine create loop to match count types, add more random calls to main
remove redundant braces
reorder value list to create a more interesting tree shape