Fix README file name in long_description

README file was converted to rst format hence renamed to README.rst but
was not renamed in setup.cfg.
Add char_compare and get_language functions

Added above functions to charmap module, these functions are duplicated
in various related module so silpa_common is right place for these
functions.

Also added related test cases

Signed-off-by: Vasudev Kamath <kamathvasudev@gmail.com>
repoze.lru is dependency for python2
install repoze.lru for py2 and pypy