format_topcoll: Treat themes using Boost as a parent the same as Boost

[tonyjbutler]

Currently the layout is broken if using a custom theme based on Boost (and using it as a parent).

[gjb2048]

Interesting for contributed themes. But.... might be an issue of functional conflict if the child theme overrides the get_row_class and get_column_class as intended and find they don't work. The actual solution looks as if it could be more efficient.

[gjb2048]

Ok, $THEME->parents in a theme config.php file is an array, e.g.

$THEME->parents = array('bootstrapbase');

so why are you not using the PHP 'in_array' function if '$page->theme->parents' is not empty? Then use the '===' comparitor. Ok, I need to change things too.

Please improve and re-submit as a single commit.

[tonyjbutler]

OK, I've improved the efficiency as per your suggestion.

[gjb2048]

Thanks Tony.