change 'unsigned char' to 'uint8_t' to ensure the portability
PEViewer now uses a custom structure to dump the PE headers

That way, we will not open a thousand time the file.
Rewrite of the get_section functions to dump all the sections in one.
Update documention of the functions.
New version of Packer32 bits using the PE structure.

Still need some improvements like checking if there is enough space to
write the new section.