Reduces amount of unsafe code and redoes memory management

Overall this reduces the usage of unsafe blocks to where it is actually necessary.

Also fixes issues with memory management, where instead of holding data in a buffer, we now only use Vecs for memory allocation and deallocation and in between let Rust forget about the memory's existence.

That fixes a SIGSEGV, when allocating the same type multiple times with differing length, due to previous action with it.

Closes #25 (closed)