whitespace thing here.

it'd be nice to our growing fleet of debugging aids be factored out into their own header file eventually.

just thinking out loud, but it'd also be nice to have each debug look at a flag (settable via nif) so that one could control what debugging output is getting emitted (i.e. each `DEBUG` call point would take a #defined value like `BITCASK_GET_PATH` or `BITCASK_EPOCH` which the printing would `if` on).  The nif would translate a list of atoms into C flags so you could do things like `bitcask_nifs:set_debug_flags([gets, folds]).`.