added rails 4.2.0 gem and patched state machine gem
replaced config.serve_static_assets with config.serve_static_files
use new format for custom validations
adapted session specs. #198
fixed alignment of donut charts
better display of donut charts on smaller screens
background jobs for import task. #208
Merge branch 'master' of github.com:articlemetrics/lagotto

Conflicts:
	lib/tasks/db.rake
migrate delayed_job to ActiveJob. #208
use ActiveJob deliver_later for mail. #208
renamed and simplified ActiveJob-related attributes. #208
removed association to DelayedJob class
remove queued_at flag for retrieval_statuses in History class
small tweaks related to ActiveJob. #208
tweaks in import options
added tests for active jobs. #208
tweaks on import scripts
small tweaks for rspec tests
version bump