Remove HACKING file

The C4 contribution process was killed, so this file is no longer
relevant.
Merge pull request #274 from larsbutler/rm-hacking

Remove HACKING file
deleted debian log files

debuild log files do not need to be in repository
Merge pull request #277 from pkit/log-fix

deleted debian log files
doc/api.txt: trap supports 6 functions, not 5
Merge pull request #280 from larsbutler/api-doc-correction

doc/api.txt: trap supports 6 functions, not 5
doc/api.txt: correct count of system calls

"trap" is not a system call; pread, pwrite, jail, unjail, fork, and exit
are the ZeroVM system calls. "Trap" is the syscall interface with which
these syscalls are implemented.
Merge pull request #281 from larsbutler/syscalls-correction

doc/api.txt: correct count of system calls