Fix coding style.

git-svn-id: https://svn.nmap.org/nmap-exp/d33tah/ncat-test-py@32611 e0a8ed71-7df4-0310-8962-fdc924857419
Introduce ScopedPopen, my attempts at simplifying the testing code.

git-svn-id: https://svn.nmap.org/nmap-exp/d33tah/ncat-test-py@32612 e0a8ed71-7df4-0310-8962-fdc924857419
Factor out handle_test to make it trivial to switch the code to a
single-threaded mode for easier debugging.

git-svn-id: https://svn.nmap.org/nmap-exp/d33tah/ncat-test-py@32613 e0a8ed71-7df4-0310-8962-fdc924857419