Add note about using release profile to create bin

I don't know too much about Java or Maven, and it took me a while to figure out how to create the binaries that are precompiled and included in the zip download. It's probably second nature for y'all, but this line would've saved me a few hours of headache. What do y'all think?

Author: gempesaw

README.md

@@ -209,3 +209,11 @@ NodeJS Support
 --------------
 
 NodeJS bindings for browswermob-proxy are available [here](https://github.com/zzo/browsermob-node).  Built-in support for [Selenium](http://seleniumhq.org) or use [CapserJS-on-PhantomJS](http://casperjs.org) or anything else to drive traffic for HAR generation.
+
+Creating the batch files from source
+------------------------------------
+
+You'll need maven (`brew install maven` if you're on OS X); use the `release` profile to generate the batch files from this repository. Optionally, proceed at your own risk and append the `-DskipTests` option if the tests are failing.
+
+    [~]$ mvn -P release
+    [~]$ mvn -DskipTests -P release