Adjust comments around split_into_argv() to clarify that it's not
*Windows's* command-line splitting rules we're mimicking here; it's
VC7's, and they're not the same as VC10's.


git-svn-id: svn://svn.tartarus.org/sgt/putty@9748 cda61777-01e9-0310-a592-d414129be87e