[PATCH] Ruby 1.9 rescues/_trace.erb

Two separate problems.

The first is that Array#to_s in Ruby 1.9 behaves like Array#inspect, whereas in Ruby 1.8 it behaved more like Array#.join. Depending on the behavior #to_s is therefore problematic, and causes the onclick=hide string to become mangled.

The second is that call traces often contain artificial method names like <internal:prelude>, which won't show up at all unless escaped.

This patch addresses both issues.