Update Gemfile.lock.
v2.4.0
Bump rake to 10.4.
Update uglifier to 2.6.
Update Jekyll to 2.5.
Update bundle.
Update highlightjs to 8.4.
v2.4.1
Merge tag 'v2.4.1'

Conflicts:
	Gemfile.lock
Update jekyll-scholar to 4.2.1.