add pscheck module and call to entry point
First try at a psutil based process checker
Rearrange the try statement
Try using p.exe instead of the open files
realpath, not relpath
Update the error message
Change the default answer to no if processes are running
Make pscheck.main() return True on OK and False on not OK
Don't check the Python that conda is running in

I don't actually know if this works until Monday when I can test it on Windows
again.
Check os.getpid() instead of sys.executable
Print full command of process
Fix typo
Make error message a little clearer to users
Reword something
Catch WindowsError
Exit 1 when the user cancels
Pscheck reasks until it is safe to install

The logic is now entirely in pscheck, and moved to the individual functions
instead of confirm (because create, which calls confirm, does not need this).
It ask to proceed, but if there are still processes open, it will check again
and ask again.  You can force an install by passing --yes, which will still
print the warning, but not stop the installation.
Merge pull request #114 from asmeurer/psutil

Psutil