Move all internal functions to the new header file ykcore_lcl.h.

Move all internal functions to the new header file ykcore_lcl.h.
Rename structures in ykcore.h so they are in the namespace.
Add a hack in ykcore_lcl.h to map ykcore.h structure names to ykdef.h ones.
Have ykcore_lcl.h include ykcore.h and ykdef.h, so we get the order right.
Change relevant .c files accordingly.

git-svn-id: https://yubikey-personalization.googlecode.com/svn/trunk@78 b62f149e-849f-11dd-9899-c7ba65f7c4c7