make sample.c configurable about hugepage
sample.c: add hugepage size check
rename valname SAMPLE to TESTPROG
fix cleanup target of lib/Makefile
lib/setup_test_core.sh: fix tag line format
redefine pprinf/Dprinf

pprintf() writes to testpipe if it's set, otherwise writes to stdout.
Dprintf() calls pprinf() if verbose is set.

Signed-off-by: Naoya Horiguchi <nao.horiguchi@gmail.com>