Detects 32bit mode on x86_64 and gets syscall info

trace_handle_syscall() still needs to get updated to handle these 32-bit
syscalls.
Correctly gets registers for x32 mode on x86_64
Merge branch 'master' into 'x86_64-32bit-syscalls'

Conflicts:
	reprozip/native/tracer.c
Refactor: Moves syscall handling out of trace.c
Fixes __X32_SYSCALL_BIT definition
Clears out x32/i386 confusion
Converts syscalls.c and syscalls.h to LF EOLs

Oops.
Merge branch 'master' into 'x86_64-32bit-syscalls'
Major refactor, introduces dispatch table
Fixes perror() calls
Includes stdio.h in log.h
Logs PEEKDATA failures
Correctly handles errors in syscall handlers
Fixes dispatch table
Fixes warning
Special handling for rt_sigreturn

Apparently, on return from rt_sigreturn, orig_rax might be set to
something other than SYS_rt_sigreturn.
Merge branch 'master' into 'x86_64-32bit-syscalls'

Conflicts:
	reprozip/native/database.c
	reprozip/native/log.h
	reprozip/native/ptrace_utils.c
	reprozip/native/tracer.c
	reprozip/native/utils.c
	reprozip/setup.py
Merge branch 'master' into 'x86_64-32bit-syscalls'
Removes SYS_execve mention from syscall_execve_out
Correctly handles execve() x64 -> i386 transition