Please add testing instructions

Testing instructions:

1. Create nested web_links categories and populate them with web links such as:

Main Category
    First Subcategory
        link1
        link2
        link3
    Second Subcategory
        link4
        link5
        link6
    Third Subcategory
        link7
        link8
        link9

1. Create a new module of type Web Links
2. Select Master Category as the category and set Group By Subcategories to Yes.
3. The following new settings will affect the module as follows:
   • Group By Subcategories => if set to yes, all web links belonging to subcategories of Main Category will be displayed, grouped by categories; default behaviour otherwise.
   • Show Group Title => if set to Yes, a title will be displayed for each group.
   • Group Ordering => subcategories will be ordered ether by Title or Order.
   • Group Ordering Direction => self-explanatory.
   • Columns => each subcategory will output into span(12 / columns) class div, grouped by columns into row row-fluid divs.

All new settings will be ignored if Group By Subcategories is set to No and the default behaviour of the module hasn't changed.

• Added missing 1-column option.

Added requested fixes.

@Test works fine here

@Test works for me like expected, thanks for coding the feature

@manureggi Assuming this PR is still valid, can you fix the merge conflicts please?

@chrisdavenport The merge conflicts were only due to the fact that the mod_weblinks.xml file had been moved since I issued the pull request. I've now rebased onto the current master branch.

@manureggi Looks good. Perhaps add a showon="groupby:1" attribute to the Show Group Title, Group Ordering and Group Ordering Direction fields?

Since I haven't heard back from @manureggi I'm going to just merge this as it stands. I'll submit a new PR for the minor UI change that I proposed.

Thanks @manureggi for coding this feature and thanks to everyone else for testing and feedback.