update version
add option to automatically center the volume
update TODO
update version number
Add return statement to CAPTURE_NULL

Since 'Throw' does not automatically return from a function, the
capturing code did not protect the function from working with
NULL pointers as array, resulting in segfaults.
Two versions of returning CAPTURE_NULL are now used, one for void
and one for non-void returning functions.
replace old capturing code
implement returning capture macros for gfunc3 init status
update capturing macros, improve exception handling and do some cleanup

- new returning capture macros for NULL and gfunc3 init status
- Try-Catch now effectively protects code from working with undefined array etc. (issue #8)
- remove code for second axis
improve exception handling

- add return statements to Throw macros
- use returning capture macros
add return to Throw
update TODO
properly implement exception handling
update description
properly implement exception handling
update version
fix exception handling
move definition of complex zero and one to misc.h
update descriptions and add info about throwing behavior
fix exception handling, part 1 (issue #8)
update descriptions