issue2551097 - fix call to markdown2 - fix fenced code blocks. The invocation of fenced codeblock support in markdown2 was wrong. With this fixed the code that was used to test markdown processor exception handling no longer works. Fixed test case to make it pass. Added new test with invalid markdown that tests markdown exception handling. Also renamed test to include markdown. Makes using -k option in run_tests easier.

#!/usr/bin/env python

# Roundup requires Python 2.7+ as mentioned in doc\installation.txt
from __future__ import print_function
import sys

VERSION_NEEDED = (2, 7)

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)