cleaned up phpdoc comments, added README on how to install and use it

doc/README.md

@@ -0,0 +1,19 @@
+Generating documentation
+========================
+
+In order to generate the documentation, you will need to install the following
+packages and its dependencies:
+* phpdoc
+* graphviz
+
+Details about [installing phpDocumentor](http://phpdoc.org/docs/latest/getting-started/installing.html)
+can be found in its own documentation.
+
+Example for Debian and Ubuntu:
+    $ sudo aptitude install pear graphviz
+    $ sudo pear channel-discover pear.phpdoc.org
+    $ sudo pear install phpdoc/phpDocumentor
+
+To generate the documentation, change into the main directory and run phpdoc:
+    $ cd ZeroBin
+    $ phpdoc -d lib/ -t doc/