* Placed C++ extern "C" blocks inside include guards.
* Added a "clean_all" rule to the Makefile to avoid recompiling libusbhsfs after each time "clean" is used.
* Added static asserts for all structs that may need it throughout the code.
* Preprocessor macros are now used to generate certificate and ticket structs.
From now on, I'll delete code from the legacy codebase directory as soon as specific features from it are rewritten... Because it's a mess to navigate.
