Add core dump snapshot handler script

Add core dump snapshot handler script

This is a custom core dump program that will be called when a core dump
occurs.  The program will save the core data in CORE_PATH and also, if a
root session daemon is running, will record a snapshot of tracing data
using the lttng command line utility.

Refer to README for installation and testing instructions.

Sample output of test script:

Setup...
Spawning a session daemon
Session auto-20130626-224838 created.
Kernel channel chan enabled for session auto-20130626-224838
kernel event sched_switch created in channel chan
Tracing started for session auto-20130626-224838
Sleeping...
Crashing...
./test.sh: line 35: 16980 Segmentation fault      (core dumped)
$(dirname $0)/crash
Waiting for data availability
Tracing stopped for session auto-20130626-224838
Session auto-20130626-224838 destroyed
Core dump and snapshot will be available in /tmp/lttng/{core,snapshot}.

/tmp/lttng
|-- core
|   `-- core.16980
`-- snapshot
    `-- snapshot
        |-- chan_0
        |-- chan_1
        |-- chan_2
        |-- chan_3
        |-- chan_4
        |-- chan_5
        |-- chan_6
        |-- chan_7
        `-- metadata

Signed-off-by: Christian Babeux <christian.babeux@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>