Add support for plain old function return types in class detection

Now both
    simplexml_parse_file()->
and
    $xml = simplexml_parse_file();
    $xml->
format supported with user defined functions as well
Update built-in informations

Generated a new built-in hash from an updated documentation.
Also added ability to generate non-prettyprinted vim hashes with reduced
set of extensions included intended for a smaller version of the script
that can be distributed with vim.
Improve completion for built-in interface names

The plugin now provides the name for the built-in interfaces as found in
the docs instead of a lowercased one.
Improve context detection around interfaces in class declarations

Made GetCurrentInstruction return the class declaration as a whole even
if theres a `,` in it (list of implemented interfaces)
Made the only completion for the second word after an extended class to be
`implements`
Add version distributed with vim

With vim revision 657ade71d395 (see https://code.google.com/p/vim/) the
plugin been pushed to the vim trunk. I've added the distributed version
of the plugin for the record.
Related to #5