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

test/tests/translateTest.js

@@ -680,6 +680,49 @@ describe("Zotero.Translate", function() {
 				assert.isNumber(translation.newItems[0].id);
 				assert.ok(collection.hasItem(translation.newItems[0].id));
 			});
+
+		});
+		describe('#saveItems', function() {
+			it("should deproxify item and attachment urls when proxy provided", function* (){
+				var itemID;
+				var item = loadSampleData('journalArticle');
+				item = item.journalArticle;
+				item.url = 'https://www-example-com.proxy.example.com/';
+				item.attachments = [{
+					url: 'https://www-example-com.proxy.example.com/pdf.pdf',
+					mimeType: 'application/pdf',
+					title: 'Example PDF'}];
+				var itemSaver = new Zotero.Translate.ItemSaver({
+					libraryID: Zotero.Libraries.userLibraryID,
+					attachmentMode: Zotero.Translate.ItemSaver.ATTACHMENT_MODE_FILE,
+					proxy: new Zotero.Proxy({scheme: 'https://%h.proxy.example.com/%p', dotsToHyphens: true})
+				});
+				var itemDeferred = Zotero.Promise.defer();
+				var attachmentDeferred = Zotero.Promise.defer();
+				itemSaver.saveItems([item], Zotero.Promise.coroutine(function* (attachment, progressPercentage) {
+					// ItemSaver returns immediately without waiting for attachments, so we use the callback
+					// to test attachments
+					if (progressPercentage != 100) return;
+					try {
+						yield itemDeferred.promise;
+						let item = Zotero.Items.get(itemID);
+						attachment = Zotero.Items.get(item.getAttachments()[0]);
+						assert.equal(attachment.getField('url'), 'https://www.example.com/pdf.pdf');
+						attachmentDeferred.resolve();
+					} catch (e) {
+						attachmentDeferred.reject(e);
+					}
+				})).then(function(items) {
+					try {
+						assert.equal(items[0].getField('url'), 'https://www.example.com/');
+						itemID = items[0].id;
+						itemDeferred.resolve();
+					} catch (e) {
+						itemDeferred.reject(e);
+					}
+				});
+				yield Zotero.Promise.all([itemDeferred.promise, attachmentDeferred.promise]);
+			});
 		});
 	});
 });