added contributing information to the README.md file
Merge pull request #6 from mchampanis/osx_pid_fix

PID fix for OS X. Fixes #3 cc @mchampanis and @phyllisstein
now only os.kill(PID, 0) is used on POSIX platforms to determine if the
plugin host process exists
small typo fix on README.md file
removed print statement
fixed bug introduced in c46ebd1e63a63ee45cd5e7872e71cfbdbe7a5f4a, better logging support for anaconda JSONServer