Update README.md. Add project architecture overview and translation.

README.md

@@ -1,25 +1,81 @@
 SwitchyOmega
 ============
 
-A proxy extension for Chromium.
+Manage and switch between multiple proxies quickly & easily.
 
-Development status
+Chromium Extension
-==================
+------------------
+The project is available as a Chromium Extension.
 
-## Chromium Extension
+You can try it on [Chrome Web Store](https://chrome.google.com/webstore/detail/padekgcemlokbadohgkifijomclgjgif),
-The project is now usable as a Chromium Extension.
+or grab a packaged extension file for offline installation on the [Releases page](https://github.com/FelisCatus/SwitchyOmega/releases).
-
-You can try it on [Chrome Web Store](https://chrome.google.com/webstore/detail/padekgcemlokbadohgkifijomclgjgif)
-
-## Development Schedule
-The project is now in alpha, and still considered unstable. Any feedback is
-welcomed.
 
 Please [report issues on the issue tracker.](https://github.com/FelisCatus/SwitchyOmega/issues)
 
-## Build
+Development status
+------------------
 
-SwitchyOmega has migrated to use npm and grunt for building.
+## PAC generator
+This project contains a PAC generating module called `omega-pac`, which handles
+the profiles model and compile profiles into PAC scripts. This module is standalone
+and can be published to npm when the documentation is ready.
+
+## Options manager
+The folder `omega-target` contains browser-independent logic for managing the
+options and applying profiles. Every public method is well documented in the comments.
+Functions related to browser are not included, and shall be implemented in subclasses
+of the `omega-target` classes.
+
+`omega-web` is a web-based configuration interface for various options and profiles.
+The interface works great with `omega-target` as the back-end.
+
+`omega-web` alone is incomplete and requires a file named `omega_target_web.js`
+containing an angular module `omegaTarget`. The module contains browser-dependent
+code to communicate with `omega-target` back-end, and other code retrieving
+browser-related state and information.
+See the `omega-target-chromium-extension/omega_target_web.coffee` file for an
+example of such module.
+
+## Targets
+The `omega-target-*` folders should contain environment-dependent code such as
+browser API calls.
+
+Each target folder should contain an extended `OmegaTarget` object, which
+contains subclasses of the abstract base classes like `Options`. The classes
+contains implementation of the abstract methods, and can override other methods
+at will.
+
+A target can copy the files in `omega-web` into its build to provide a web-based
+configuration interface. If so, the target must provide the `omega_target_web.js`
+file as described in the Options manager section.
+
+Additionally, each target can contain other files and resources required for the
+target, such as background pages and extension manifests.
+
+For now, only one target has been implemented: The Chromium Extension target.
+This target allows the project to be used as a Chromium extension in most
+Chromium-based browsers.
+
+However, the project architecture allows more targets to be added in the future.
+The first step would be adapting more browsers including Firefox. I don't have
+time for that now. Feel free to open a pull request if you want to help.
+
+## Translation
+
+All translations are in the `omega-i18n` folder. For now, only `en` \(English\)
+and `zh` \(简体中文\) translations are done. If you notice a translation issue
+such as typo or bad spelling, please open an issue or a pull request.
+
+You can also help to translate SwitchyOmega into your language. Just fork the
+project and copy the `en` folder to a new folder named the locale code of your
+choice. Then edit the `message.json` to provide translations. The file is in
+[Chrome Extension Locale-Specific Messages Format](https://developer.chrome.com/extensions/i18n-messages).
+Don't forget to open a pull request when you are done translating.
+
+## Building the project
+
+SwitchyOmega has migrated to use npm and grunt for building. Please note that
+npm 2.x is required for this project.
 
 To build the project:
 
@@ -41,7 +97,7 @@ To enable `grunt watch`, run `grunt watch` once in the `omega-build` directory.
 This will effectively run `grunt watch` in every module in this project.
 
 License
-=======
+-------
 ![GPLv3](https://www.gnu.org/graphics/gplv3-127x51.png)
 
 SwitchyOmega is licensed under [GNU General Public License](https://www.gnu.org/licenses/gpl.html) Version 3 or later.