userspace/sysdig: always notify the formatter of the end of file
userspace/sysdig: flush cout to print the event

When the format is JSON, the last event received is not printed
until another event is processed or sysdig terminates.
fix building of libscap on archs w/o live capture support (*BSD, Hurd)
fix build after d5b334cebb96840885f6a5cd7557dd4672bfd931

without this, the build will first fail with

In file included from /home/evgeni/Devel/sysdig/userspace/libsinsp/sinsp.h:84:0,
                 from /home/evgeni/Devel/sysdig/userspace/libsinsp/chisel.cpp:31:
/home/evgeni/Devel/sysdig/userspace/libsinsp/fdinfo.h:160:47: error: ‘sinsp_fdinfo_t<int>::callback_type’ has not been declared
  void register_event_callback(sinsp_fdinfo_t::callback_type etype, sinsp_protodecoder* dec);
                                               ^
userspace/libsinsp/CMakeFiles/sinsp.dir/build.make:54: recipe for target 'userspace/libsinsp/CMakeFiles/sinsp.dir/chisel.cpp.o' failed
make[2]: *** [userspace/libsinsp/CMakeFiles/sinsp.dir/chisel.cpp.o] Error 1

and later with

/home/evgeni/Devel/sysdig/userspace/libsinsp/fdinfo.cpp:196:6: error: specializing member ‘sinsp_fdinfo<int>::register_event_callback’ requires ‘template<>’ syntax
 void sinsp_fdinfo_t::register_event_callback(sinsp_fdinfo_t::callback_type etype, sinsp_protodecoder* dec)
      ^
userspace/libsinsp/CMakeFiles/sinsp.dir/build.make:169: recipe for target 'userspace/libsinsp/CMakeFiles/sinsp.dir/fdinfo.cpp.o' failed
make[2]: *** [userspace/libsinsp/CMakeFiles/sinsp.dir/fdinfo.cpp.o] Error 1
Merge pull request #212 from evgeni/fix-non-linux-build

fix building of libscap on archs w/o live capture support (*BSD, Hurd)
Merge pull request #213 from evgeni/fix-register_event_callback-ftbfs

fix build in register_event_callback after d5b334cebb96840885f6a5cd7557dd4672bfd931
Merge pull request #210 from ret2libc/master

improve json output
consolidated the protocol decoder callback types into a single enum
comment a currently unusued piece of syslog code
userspace/libsinsp: remove duplicated code
a bit more work on syslog decoding
userspace/libsinsp/filterchecks: make extract_as_js virtual
userspace/libsinsp/eventformatter: print ']' only if we have printed '['
more work on the syslog filtercheck. Still disabled.
more work on syslog decoding
Merge pull request #214 from ret2libc/json-str-refactoring

userspace/libsinsp: remove duplicated code
bugfix: avoid a potential infinite recursion
bugfix: avoid a potential infinite recursion
fix the check added in the previous commit
removed a warning