Add ConfigFile class for run-time reading and parsing of config files

Add ConfigFile class for run-time reading and parsing of config files

New code reads config file and splits it into lines to vector, with one
element per file line. Each line is represented as vector itself, with
one element per white space separated token.
Lines that are empty or start with '#' are ignored.

New code is now used for parsing Smack policy templates and privilege to
group mapping.

Change-Id: I009cf2a33f0233a170666cfe27fd7604fb7f4340
Signed-off-by: Rafal Krypa <r.krypa@samsung.com>