issue2551029: Jinja2 template install error. Issue where template's config.ini not getting updated. Change do_install in admin.py to load config_ini.ini from template before writing tracker's config.ini. This generates an updated config file for the user on install preserving values required tomake tracker work. Added config_ini.ini files to jinja2 and responsive templates to set required values (template_engine and static_files; static_files resp.). Documented new file in doc/tracker_templates.txt and added tests for new admin.py code.

#!/usr/bin/env python

# Roundup requires Python 2.7+ as mentioned in doc\installation.txt
from __future__ import print_function
VERSION_NEEDED = (2,7)

import sys
if sys.version_info < VERSION_NEEDED:
    print("Content-Type: text/plain\n")
    print("Roundup requires Python %s.%s or newer." % VERSION_NEEDED)
    sys.exit(0)