src/proxy.c: modify the proxy_lookup () supporting non-browser schemes

As discussed, the proxy lookup for browser and non browser schemes should
be handled in an order as follows:
A request for a "browser" protocol would match the following configs
order of preference (if they exist):
 • Matching "Domains", BrowserOnly==TRUE
 • Matching "Domains", BrowserOnly==FALSE
 • Domains==NULL, BrowserOnly==TRUE
 • Domains==NULL, BrowserOnly==FALSE

A request for a non-browser protocol would match the following:
 • Matching "Domains", BrowserOnly==FALSE
 • Domains==NULL, BrowserOnly==FALSE (except if a config exists with
   Matching "Domains", BrowserOnly==TRUE, in which case we need to
   return NULL).

Update test cases to use pacrunner_proxy_set_domains() with three
arguments.
4 files changed