README.md: Update links for Windows build
README.md: Update links for Windows build

- Python 2.7.3 is out, fix link
- mysgit changed it's url
AlphaStaxLLC/rackspace-monitoring-agent,cp16net/virgo-base,cp16net/virgo-base,christopherjwang/rackspace-monitoring-agent,kaustavha/rackspace-monitoring-agent,virgo-agent-toolkit/rackspace-monitoring-agent,cp16net/virgo-base,virgo-agent-toolkit/rackspace-monitoring-agent,cp16net/virgo-base,cp16net/virgo-base,kaustavha/rackspace-monitoring-agent,christopherjwang/rackspace-monitoring-agent,AlphaStaxLLC/rackspace-monitoring-agent