Correct options for space-index-pages-free-plot

Previously this failed with:

bin/innodb_space:794:in `basename': can't convert nil into String (TypeError)
        from bin/innodb_space:794:in `block in <main>'
        from bin/innodb_space:760:in `each'
        from bin/innodb_space:760:in `<main>'
Correctly indent space-page-type-summary help text

Also remove spurious space.
Merge pull request #9 from maginatics/help-text-indent

Correctly indent space-page-type-summary help text
Merge pull request #8 from maginatics/space-index-pages-free-plot-space-file

Correct options for space-index-pages-free-plot
Merge pull request #7 from darnaut/master

Add support for numeric and date and time types