JIRA: https://jira.springsource.org/browse/INT-3055 * Add to HTTP Outbound Endpoint `uri-variables-expression` * Add mutually exclusive check for `uri-variables-expression` with `<uri-variable>` * Tests and Docs INT-3055: Fixes * `ExpressionEvalMap` now can apply `Map<String, Object>`, but the value must have a `String` or `Expression` type. Polishing INT-3055 Doc Polishing