Don't retry fetching results on failure, 500 or otherwise. Fix bug 848480.

I'm not sure why we were being so failure-tolerant in the JS before; perhaps the CGI failed or timed out a lot. With WSGI, we no longer have timeouts to worry about, and, if we have other failures, we should solve the root problem.

If there is an error, the user can "retry" just by changing the search query or hitting Return, both of which should be natural reactions.
Emit decldef for C variables even when there's just a tentative definition

The issue is that getDefinition() will return 0 for things in C at
file scope like

        /* In a header */
	extern int i;

        /* In a C (not C++) file */
	int i;           /* This isn't a definition --- it's tentative */

In C++ that is a definition. While technically it's not a definition,
matching up variable references seems to work better in C code that
I've seen if we assume that such tentative definitions are in fact
definitions, as they are in C++.
Make var names lowerCamelCase for consistency with the rest of the project.
Merge treatment of tentative C definitions as regular definitions. Close #144.