Add web support (#22)

- [x] Refactor to support browser
  + `SentryClient` from `package:sentry/sentry.dart` with conditional import
  + `SentryBrowserClient` for web from `package:sentry/browser_client.dart`
  + `SentryIOClient` for VM and Flutter from `package:sentry/io_client.dart`
- [x] Write test for browser
- [x] Working Angular Sentry packages => https://github.com/leftyio/angular_sentry

Main implementation differences are:
- gzip compression is provided implicitly by the browser
- javascript stacktraces need to be prefix with `window.location.origin` to be resolve by Sentry

Author: lejard-h

.idea/sentry.iml

@@ -1,3 +1,7 @@
+sudo: required
+addons:
+  chrome: stable
+
 language: dart
 dart:
   - stable

.travis.yml

@@ -1,5 +1,12 @@
 # package:sentry changelog
 
+## 3.0.0
+
+- Support Web 
+  - `SentryClient` from `package:sentry/sentry.dart` with conditional import
+  - `SentryBrowserClient` for web from `package:sentry/browser_client.dart`
+  - `SentryIOClient` for VM and Flutter from `package:sentry/io_client.dart`
+
 ## 2.3.1
 
 - Support non-standard port numbers and paths in DSN URL.

CHANGELOG.md

@@ -0,0 +1,7 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+export 'src/base.dart';
+export 'src/version.dart';
+export 'src/browser.dart';

lib/browser_client.dart

@@ -0,0 +1,7 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+export 'src/base.dart';
+export 'src/version.dart';
+export 'src/io.dart';