feat(http): add basic http service

This implementation only works in JavaScript, while the Observable transpilation
story gets worked out. Right now, the service just makes a simple request,
and returns an Observable of Response.

Additional functionality will be captured in separate issues.

Fixes #2028

modules/angular2/src/http/url_search_params.ts

@@ -0,0 +1,45 @@
+import {isPresent, isBlank, StringWrapper} from 'angular2/src/facade/lang';
+import {Map, MapWrapper, List, ListWrapper} from 'angular2/src/facade/collection';
+
+function paramParser(rawParams: string): Map<string, List<string>> {
+  var map: Map<string, List<string>> = MapWrapper.create();
+  var params: List<string> = StringWrapper.split(rawParams, '&');
+  ListWrapper.forEach(params, (param: string) => {
+    var split: List<string> = StringWrapper.split(param, '=');
+    var key = ListWrapper.get(split, 0);
+    var val = ListWrapper.get(split, 1);
+    var list = MapWrapper.get(map, key) || ListWrapper.create();
+    ListWrapper.push(list, val);
+    MapWrapper.set(map, key, list);
+  });
+  return map;
+}
+
+export class URLSearchParams {
+  paramsMap: Map<string, List<string>>;
+  constructor(public rawParams: string) { this.paramsMap = paramParser(rawParams); }
+
+  has(param: string): boolean { return MapWrapper.contains(this.paramsMap, param); }
+
+  get(param: string): string { return ListWrapper.first(MapWrapper.get(this.paramsMap, param)); }
+
+  getAll(param: string): List<string> {
+    return MapWrapper.get(this.paramsMap, param) || ListWrapper.create();
+  }
+
+  append(param: string, val: string): void {
+    var list = MapWrapper.get(this.paramsMap, param) || ListWrapper.create();
+    ListWrapper.push(list, val);
+    MapWrapper.set(this.paramsMap, param, list);
+  }
+
+  toString(): string {
+    var paramsList = ListWrapper.create();
+    MapWrapper.forEach(this.paramsMap, (values, k) => {
+      ListWrapper.forEach(values, v => { ListWrapper.push(paramsList, k + '=' + v); });
+    });
+    return ListWrapper.join(paramsList, '&');
+  }
+
+  delete (param): void { MapWrapper.delete(this.paramsMap, param); }
+}