html5 target now supports dependencies

Hello,

It is now possible to include a javascript files, through an haxelib.
The way to do it similar to how the dependencies work in Android and iOS. You basically specify a path to the js file in the dependency tag

For example:

SomeHTML5Haxelib/dependencies/JSLib/jslib.js

        <JS CODE>

SomeHTML5Haxelib/include.xml

        <extension>

	         <dependency path="dependencies/jslib.js" if="html5" />
	
        </extension>

The resulting template execution on index.html will inject the contents of include.htm via the:

         ::if (JAVASCRIPT_LIBRARIES)::
              ::foreach (JAVASCRIPT_LIBRARIES)::
                      <script type="text/javascript" src="./::PATH::"></script>   
              ::end::
        ::end::

So the final index.html will successfully load the javascript file and it will be available for use in Haxe code through the usual "extern" or "untyped __js__".

Its a pretty simple feature, but helps a lot with bringing even more autonomy to haxelibs.

This pull request is connected to another one in lime-tools. https://github.com/openfl/lime-tools/pull/73

Thanks!
Rui.