cppcms: new package

[Thomas: reformat header and Config.in help text, add dependency on
glibc since cppcms uses <monetary.h> functions that aren't available
in uClibc.]

Signed-off-by: Nicolas Ménégale <nicolas.menegale@openwide.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>