Changed creation of a temporary file

the code now checks before using a particular command (multiple
commands are supported) and will fall back to creating a simple file in
/tmp
Changed the -t type invocation of mktemp
another change, mktemp is "preferred" now
Small fix to touch_tempfile

it now behaves like the other two commands, echo-ing the created
filename
Small fixes

added some double-quotes, just in case
take only the basename of the script, so no path info is added when
constructing temp filename
Merge pull request #97 from goranche/master

Changed creation of a temporary file, it now prefers mktemp, but will use tempfile if used. if all else fails, it creates a temp file in /tmp