Resolve "No replica set members found yet" errors when using mongodb connections when API is hosted by API.

- add two new variables to sample.config
- update defaults in config.py to be strings as that's how environment
  variables come in by default

closes #93

closes #100

closes #115

cgi.FieldStorage by default doesn't use make_file.
Only if the file is bigger than 1000 bytes the method is called.
Overriding the private method __write allows to always call the method
independently of file size.

closes #88