[install] Make the install helper scripts more resilient to spaces. install.exec is still painful. Closes PR #5.

From: Dustin L. Howett <dustin@howett.net>

git-svn-id: http://svn.howett.net/svn/theos/trunk@619 4410221e-0ddf-4ce3-99c0-2db6c0dbc727