This patch adds some of the common functionalities from std:string to
sstring.
It adds length (implement by size() )
It define the constant npos to indicate no possition.
It adds the at (reference and const reference)
It define the find char and find sstring methods
and the substr method
Signed-off-by: Amnon Heiman <amnon@cloudius-systems.com>
need merge sstring
29391d9a9b