simple infrastructure to report sysdig driver events to userlevel
missing event definition
a tiny bit more logging
some tuning of drop mode
make sure the process arguments string is not empty before copying from proc
make sure the process environment variable string is not empty before copying from proc
-u command line flag, to prevent importing user and grop tables when the capture starts
-u command line flag documentation added to the manual
-u works from file as well
use -E/--exclude-users instead of -u/--nouser
Fix expression parsing, closes #255
Merge branch 'dev' into setresuid

Conflicts:
	driver/event_table.c
	driver/ppm_events_public.h
	driver/ppm_fillers.c
	userspace/libscap/event_table.c