Bug Description:
The pathname parsing in nspawn function does not take into consideration spaces in the pathname.
Consider the following pathname of a CLI application: /home/user/Project Folder/Sub Folder/bin/cli (note the spaces in the pathname)
In the lines 360-362 in nexpect.js, we can see the following code:

Suppose we consider our above pathname, we can clearly observe:
- command will be:
/home/user/Project
- params will be:
params OR [ "Folder/Sub" , "Folder/bin/cli" ]
This leads to improper pathanme parsing and errors in testing.
Expected Behaviour:
The pathname should be parsed properly even if it contains spaces in it.