Update nodeenv.py

Wrap srcdir in single quotes to prevent problems with spaces etc.
Merge pull request #1 from srathbun/patch-1

Update nodeenv.py
Properly escaped all directories used by subprocesses.
Fixed merge conflict with bad change.
Merge pull request #2 from srathbun/shell_quoting_fix

Shell quoting fix
Merge pull request #40 from RiveraGroup/master

Shell quoting fixes