Improves proxy support (#1129)

Improves proxy support

- Automatically detect and dehyphenise https proxies which use EZProxy
  HttpsHyphens
- Web translators now pass around Zotero.Proxy instances which can
  proxify/deproxify urls passed to `translate.setLocation()` before calling
  `translate.getTranslators()`/ translate.detect()`. The proxy passing is
  done within connector background/injected processes and between
  standalone and connectors.
- Proxy protocol unified with connectors. Connectors can now pass
  proxies to `/connector/save_items`. The proxies will be used to resolve
  true item and attachment urls when saving.

Closes zotero/zotero#578, zotero/zotero#721

Relevant zotero/zotero#34, zotero/zotero#556

components/zotero-service.js

@@ -44,6 +44,7 @@ const xpcomFilesAll = [
 	'ipc',
 	'profile',
 	'progressWindow',
+	'proxy',
 	'translation/translate',
 	'translation/translate_firefox',
 	'translation/translator',
@@ -98,7 +99,6 @@ const xpcomFilesLocal = [
 	'locateManager',
 	'mime',
 	'notifier',
-	'proxy',
 	'quickCopy',
 	'report',
 	'router',