Remove --root command line flag

According to the discussions on #118, removing the `--root` command line flag from the documentation. See also: commit ea32e9abbca15ad89b3b2e8f5619fa665723e874.
Merge pull request #120 from rishabhsrao/master

Remove --root command line flag
Update README.md

add `.sass` note about using `//doc` style comments
Update README.md
Add support for multiple source directories to the hologram config

- Source now allows either a single value (keeping backwards compatibility)
  or a yaml array of sources.
- This is useful when pulling in a library that comes with Hologram docs
  support built in.
- We considered auto resolving conflicting namespacing for multiple
  libraries, but we weren't sure that was really an essential feature.
  We'll use this feature for a bit, and add it if it seems worth the
  effort.
- We didn't modify the CLI to take multiple sources, if you'd like that
  feature, we're happy to add it.
Merge pull request #131 from stubbornella/multi-source

Add support for multiple source directories to the hologram config
Add cortana theme to readme extensions and plugins
Relax version requirement for redcarpet
Remove deprecation warnings in test suite
Revert "Remove deprecation warnings in test suite"

This reverts commit adffdf55dd8fced5e7774bc3aa1d32983ea0c43d.
Fix nil on potentially empty dependency config var
Merge pull request #138 from carpodaster/fix/relax-redcarpet-dependencies

Relax redcarpet dependencies
Add simple plugin support
Update tests for plugin support
Pass extra flags to plugins, use plugin instances instead of static calls