PDV function no longer undefined but output is not correct

I believe I've made some progress on #4, though not resolved it.

As a first step I'm running
`:call pdv#DocumentCurrentLine()` to try and auto-document a line.

This was failing with an undefined function call.  I've made some progress by adding the vmustache plugin as a submodule and changing `~` to `$HOME` in . gvimrc

I'm now getting the following auto generated comment
```
/**
 * ${1:bsg_layout_options_modify_classes_to_add}
 *
 * @param ${2:mixed} $classes_to_add${3}
 */
```
which appears to be incomplete but closer to the end goal.