Update Gemfile to rails 4
Some extra gems and configurations
Remove attr_accessible
Merge branch 'branch-v2-refactor-emails' of https://github.com/mconf/mconf-web into branch-v2-rails4

Conflicts:
	Gemfile
	Gemfile.lock
	lib/mconf/digest_email.rb
	lib/mconf/invitation.rb
	spec/factories/join_request.rb
	spec/mailers/notifier_spec.rb
Use new validate format regex syntax
Remove duplicated vcf mime type
Update bigbluebutton rails, restructure gemfile and migrate db schema to rails4 format
Corrections to routes
Correct rails4 scopes and has_many differences
Add libs for deprecated shoulda matchers
Remove rails deprecated methods in models
Update several methods to the new syntax
Replace rails deprecated find_by methods and rename bbb-rails fields
Correct resque.rake require
Add dummy devise secret
Modified the function "with_disabled" inside the users/spaces model to get all objects (even disabled). Replaced "be_an_instance_of" to "be_kind_of" inside some tests to fix the errors after migration.

refs #1088
Use newer bootstrap-rails and correct font-awesome path
Remove rails deprecated finder
Correct rspec include matcher to use boolean matcher
Match correct partial template name