Baseline for creating an ajtcl Windows plugin for Cordova-based apps.

The approach is to wrap the ajtcl library to a Windows Runtime Component
to make it callable from JavaScript on Windows and Windows Phone platforms.
Removed the old windows8 and wp plugins.

These were not in use anymore since there is only one
universal plugin implementation for the windows platform.
Take into use a new capability to define project per device.

This requires using Cordova scripts that has implementation for this
https://issues.apache.org/jira/browse/CB-8123 feature.

When using older scripts, builds for Windows and Windows Phone does
not work out of box. With older scripts, one must comment out one
of the referenced projects and then builds will work only to the target
that remains in plugin.xml file.
Exposed AJ_StartClient() to Javascript
Fixed join session bug
Modified AJ_StartClient() so that it can now return session id in JS
Fixed invalid extern function calling
Exposed void AJ_PrintXML(const AJ_Object* objs) to JS
Fixed memory leaks in AJ_PrintXML() and AJ_RegisterObjects()
Exposed AJ_MarshalMethodCall() to Javascript
Exposed AJ_MarshalArgs(), AJ_DeliverMsg(), AJ_CloseMsg(), AJ_UnmarshalMsg(), AJ_UnmarshalArg(), AJ_CloseArg() to JS. basic_client.c can now partly be implemented in JS.
Minor tweaks and bugs fixed
Minor tweaks and bugs fixed