tests: ts_calibrate: add new timeout option for validate mode
tests: ts_calibrate: add new timeout option for validate mode

framebuffer and ts are now closed properly after validation,
except if timeout is set to -1, then the former behaviour is
simulated and they are not closed to leave the result in the
framebuffer after application exit.
Default timeout is now 5s as dicussed in #142.

Usage: -s / --timeout
-1 -> former behavior (no timeout)
 0 -> no result screen at all
>0 -> timeout in secs
 5 -> timeout 5s (default)

Example (timeout 2s):
ts_calibrate --validate -s 2
ts_calibrate --validate --timeout 2 -t 500 -b 25 -l 5

Fixes #142
Closes #143

kergoth/tslib,kergoth/tslib,kergoth/tslib,kergoth/tslib