Implemented TerminalAccess.isTerminal() and Terminal.getTerminalSize() on windows.

src/main/java/net/rubygrapefruit/platform/internal/WindowsConsoleFunctions.java

@@ -0,0 +1,7 @@
+package net.rubygrapefruit.platform.internal;
+
+public class WindowsConsoleFunctions {
+    public static native boolean isConsole(int filedes, FunctionResult result);
+
+    public static native void getConsoleSize(int filedes, MutableTerminalSize size, FunctionResult result);
+}