[kirkwat]

• Glassdoor returns jobs again: current location endpoint (encoded term), Glassdoor's app cookies, and pages are no longer discarded over a harmless per-page error
• A job that fails to parse is skipped with a warning (like LinkedIn), and an unknown location logs an error instead of crashing the call
• New fetch_description flag (default off) for boards where a description costs an extra request per job; linkedin_fetch_description still works but is deprecated
• user_agent no longer carries over between Glassdoor calls

Note: Glassdoor rate-limits after ~30 requests per IP, so its descriptions are opt-in via fetch_description=True (use proxies for
more).

Thanks @EnxhiT: the non-fatal GraphQL error handling comes from #347

Refs #270, #279, #273