* cedet/semantic.el: Add autoloads for semantic/idle functions.

* cedet/semantic.el: Add autoloads for semantic/idle functions.

* cedet/semantic/util.el (semantic--completion-cache): New var.
(semantic-symbol-start, semantic-find-tag-for-completion)
(semantic-complete-symbol): New functions, adapted from Senator.

* bindings.el (complete-symbol): Try semantic-complete-symbol if
no tag table is active.

* cedet/semantic/idle.el (define-semantic-idle-service): Doc fix.