#24 Allow Identifier Searches to be Restricted to Declarations

[AdrianIssott]

This is particularly useful for large code bases where the number of references completely swamps the number of declarations. Also OpenGrok* supports this.

Suggested implementation: add tickboxs to the Ident HTML page to allow the user to specify whether they wish to search for declarations, references or both (defaulting to both).

* http://www.opensolaris.org/os/project/opengrok/

[Andre-Littoz]

This feature will ship with 0.9.10 release.
It will be based on a idea of Martin Wilck.
I feel however that looking for references only will not give a substantial improvement since definition are less numerous than references.
Default will be defined through a personal preference parameter in lxr.conf.