driver/ppm_events_public: change ppm_param_info.symbols in info.

Change ppm_name_value* symbols in void* info, so that we can store
extra informations for parameters which can have multiple
meanings/types depending on some other parameters.
driver: add PPME_SYSCALL_PTRACE_*
driver: handle request parameter of ptrace syscall
driver/ppm_fillers: add simple ptrace_x filler
start converting ptrace "addr" param to PT_DYN
driver: prepare fillers and val_to_ring to accept dyn_idx

TODO: implement PT_DYN type
implement PT_DYN in both driver and userspace
implement ptrace filler and parse some requests
driver/ppm_fillers: refactor ptrace_x filler
userspace/libsinsp/event: fix error when handling PT_DYN params
Merge branch 'master' into ptrace_filler2

Conflicts:
	userspace/libsinsp/event.cpp
[113] Initial import of the cyclewriter

Independently maintained at github.com/kristopolous/fileEngine

There is documentation at that repository with more information.

This commit also introduces the documentation for the options
that will be integrated in a subsequent commit inside of the
./sysdig -h output.
Support splice
Merge pull request #180 from annulen/splice

Support splice
execute tests in a subfolder of $TMPDIR

- using predictable names in /tmp for doing anything is bad for security
- trying to re-execute tests after one failed atempt may result in weird
  behaviour instead of working (or failing the very same way) tests

let's call mktemp -d, work in the directory it creates and remove
everything when done
download and build lib in an non-predictable temp folder
Merge pull request #183 from evgeni/proper-tmp-use

do not place tests in predictable temp folders
allow overriding the TMPBASE if the developer wants to reuse old files

refs #183
improved, hierarchical spy users
added a document with coding conventions