Issue 131 - [Document projects consistently] Add a README.md to the adblockpluschrome repository

README.md

+Adblock Plus for Chrome, Opera and Safari
+=========================================
+
+This repository contains the platform-specific Adblock Plus source code for
+Chrome, Opera and Safari. It can be used to build Adblock Plus for these
+platforms, generic Adblock Plus code will be extracted from other repositories
+automatically (see _dependencies_ file).
+
+Building
+---------
+
+### Requirements
+
+- [Python 2.x](https://www.python.org)
+- [The Jinja2 module](http://jinja.pocoo.org/docs)
+- [The PIL module](http://www.pythonware.com/products/pil/)
+- For signed Chrome and Opera builds: [M2Crypto module](https://github.com/martinpaljak/M2Crypto)
+- For signed Safari builds: A [patched version of the xar command line tool](https://github.com/mackyle/xar/)
+
+### Building the extension
+
+Run one of the following commands in the project directory, depending on your
+target platform:
+
+    ./build.py -t chrome build -k adblockpluschrome.pem
+    ./build.py -t opera build -k adblockplusopera.pem
+    ./build.py -t safari build -k adblockplussafari.pem
+
+This will create a build with a name in the form
+_adblockpluschrome-1.2.3.nnnn.crx_ or _adblockplussafari-1.2.3.nnnn.safariextz_.
+Note that you don't need an existing signing key for Chrome or Opera, a new key
+will be created automatically if the file doesn't exist. Safari on the other
+hand always requires a valid developer certificate, you need to get one in the
+Apple Developer Center first. _adblockplussafari.pem_ should contain the private
+key for your developer certificate, the developer certificate itself as well as
+all the certificates it was signed with (Apple's root certificate and
+intermediate certificates) in PEM format - in that order.
+
+### Development environment
+
+To simplify the process of testing your changes you can create an unpacked
+development environment. For that run one of the following commands:
+
+    ./build.py -t chrome devenv
+    ./build.py -t opera devenv
+    ./build.py -t safari devenv
+
+This will create a _devenv_ directory in the repository. In Chrome and Opera you
+should load it as an unpacked extension directory. After making changes to the
+source code re-run the command to update the development environment, the
+extension should reload automatically after a few seconds.
+
+In Safari you should load _devenv/adblockplussafari.safariextension_ as unpacked
+extension directory. After making changes to the source code re-run the command
+to update the development environment. You will still need to reload the
+extension explicitly in the Extension Builder, Safari currently doesn't allow
+automating this action.
+
+Running the unit tests
+----------------------
+
+To verify your changes you can use the unit test suite located in the _qunit_
+directory of the repository. In order to run the unit tests go to the
+extension's Options page, open the JavaScript Console and type in:
+
+    location.href = "qunit/index.html";
+
+The unit tests will run automatically once the page loads.