Remove `Command.globs` method

It is no longer being used.
Get relative paths of directories to ignore

Use `Pathname#realpath` to get absolute paths so that
`Pathname#relative_path_from` will not raise an exception. Also add the
config files to this list.
Adds default front-matter support for collecitons
Includes tests for frontmatter defaults in documents
Passes the url to FrontmatterDefaults.all instead of full path
Adds the missing tests for #2405
Adds an example how to use frontmatter defaults with collections
Fixes the extra indentation in cucumber test
Use `https` for GitHub links.

The `http` links already redirect to `https` anyway.
change label to collection

To make it clear the label is of the document's collection
remove extra space
Merge pull request #2470 from XhmikosR/https
Update history to reflect merge of #2470 [ci skip]
add test for collection name
Merge pull request #2436 from budparr/documenttoliquid
Update history to reflect merge of #2436 [ci skip]
Refactor logic into Command class. Add tests.
Post about StickerMule discount.
Add img to StickerMule post.
Add "Other News" section for News sidebar on site