Resolve "Load images based on magic numbers instead of filename extension in C++"

Closes #18 (closed)

I have implemented the C++ interface of loading images based on their magic numbers. I have tested this functionality and it works well, even in parallel mode. I have also changed the python interface.

Could someone have a look on the modifications?

ping @bob Could someone please check and merge this?

Cool, thanks @mguenther. Merging.

Status changed to closed

Status changed to reopened

Status changed to merged

mentioned in commit f943a35d