Ensure joint.layout.DirectedGraph.js is precompiled

Otherwise causes errors
Merge pull request #912 from alphagov/precompile-joint-directedgraph-plugin

Ensure joint.layout.DirectedGraph.js is precompiled
Remove all trailing whitespace from .rb files
Merge pull request #914 from alphagov/fix-whitespace

Remove all trailing whitespace from .rb files
Sierra Leone, Singapore, South Africa waiting time update
Merge pull request #915 from alphagov/overseas_passports_bugs

Smartanswers: overseas passports - Sierra Leone, Singapore, South Africa waiting time update
Add general purpose support for predicate union (or)

aliased to `|`.
Update overseas-passports to use next_node_if

also refactored to use predicates which generate helpful labels
Convert maternity-paternity-calculator.rb to next_node_if
Convert register-a-birth to #next_node_if
Refactor register-a-death to use next_node_if