refactor: in a terse DSL, client's shouldn't have to type new. Covers <tspan>.
refactor: in a terse DSL, clients shouldn't have to type new. Covers <stop>.
refactor: in a terse DSL, clients shouldn't have to type new. Covers gradients.
refactor: in a terse DSL, clients shouldn't have to type new. Covers <tbreak>.
refactor: rename svg.Builder.withChild => svg.Builder.child for brevity.
refactor: inline transform DSL into Element builder, for brevity.