Cleaning up include files

Removed include files from newlib and created stubs that have functionality
that we use so far.
Removed gcc stdarg.h for license compliance

Replaced stdarg.h from gcc with one written from scratch, with info
taken from clang's UIUC/NCSA licensed stdarg.h
More work on paging

Cleaned up paging code, seems to work properly now, still needs cloning and
Copy On Write implemented, and proper frame management added.
Cleaned up code to satisfy Clang

Clang has stricter warnings, so various changes were made to accomodate
them, should now build properly in GCC and Clang.
Added 'make tftp' option to copy kernel to /tftpboot/chicken