allow theme-loader.php to work with child themes

[pembo13]

As is the code doesn't work when used in child themes. The two WP function call changes allow this.

[truongwp]

Hi @pembo13,

UPDATED:
Sorry. I'm wrong. I think we should create a file like child-theme-loader.php.
Or an another way is let developer define constants when include gallery meta box.

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Thanks for the pull request. I think we should check if is child theme, use get_stylesheet_directory(), otherwise, use get_template_directory(). If only use get_stylesheet_directory(), it will cause error in case using child theme but Gallery Meta Box is put in parent theme.

[truongwp]

Should check is_child_theme()

I'm wrong

[pembo13]

@truongwp I believe get_stylesheet_directory works for both parent and child themes. Are you finding that not to be the case?

[truongwp]

@pembo13 If Gallery Meta Box is placed in parent theme and you are using a child theme, this will cause error

[pembo13]

@truongwp good point, I'll migrate to a separate file, child-theme-loader.php