(Primarily for use in the async VOL connector, which has to schedule API
operations for future execution and then restore the state of the library when
the operation actually executes)
This implicitly adds support for changing the VOL connector for command-line
tools or any application linked with the library.
Also, add 'make check-vol' support for all directories, clearing up necessary
issues in testing scripts, etc.
comparison to return comparison value as parameter, so they can return error
values; "cancelled" -> "canceled"; switched order of 'wrap_object' and
'free_wrap_ctx' management callbacks.
This brings the H5VL code in line with the H5I code regarding
naming, parameter order, etc.
Several public API calls were affected by this change.
These changed names to reflect their use with VOL drivers:
H5VLregister() --> H5VLregister_driver()
H5VLregister_by_name() --> H5VLregister_driver_by_name()
H5VLunregister() --> H5VLunregister_driver()
H5VLis_registered() --> H5VLis_driver_registered()
This call was renamed to match H5Iregister(). The order of the first
two parameters also reversed and the object pointer is now const.
H5VLobject_register() --> H5VLregister()
