Adding user doc section and core files for new site

site/user/sample/hello.md

+Creating a Skia "Hello World!"
+==============================
+
+This tutorial will guide you through the steps to create a Hello World Desktop
+application in Skia.
+
+Who this tutorial is for:
+-------------------------
+
+This will be useful to you if you want to create a window that can receive
+events and to which you can draw with Skia.
+
+Step 1: Check out and build Skia
+--------------------------------
+
+Follow the instructions for: Linux, Mac OS X or Windows. The framework that we
+will be using does not currently support other platforms.
+
+Once you have a working development environment, we can move on to the next step.
+
+Step 2: Build the included HelloSkia Example
+--------------------------------------------
+
+We will be using the "SkiaExamples" framework. You can find it in the
+experimental/SkiaExamples directory. There is an included HelloWorld example,
+and we will start by building it before we go ahead and create our own.
+
+### On Mac OS X
+
+Run `GYP_GENERATORS="ninja" ./gyp_skia`
+This will generate a ninja target, and `ninja -C out/Debug SkiaExamples` will create `SkiaExamples.app`
+
+### On Linux:
+Run `GYP_GENERATORS="ninja" ./gyp_skia`
+
+Build the SkiaExamples target:
+
+    ninja -C out/Release SkiaExamples
+
+The SkiaExamples binary should be in `out/Release/SkiaExamples`
+
+### On Windows
+
+Run `./gyp_skia`
+
+There should be a Visual Studio project `out/gyp/SkiaExamples.vcproj`  with
+which you can build the SkiaExamples binary.
+
+### Run the SkiaExamples.
+
+You should see a window open displaying rotating text and some geometry.
+
+Step 3: Create your own Sample
+------------------------------
+
+Create a file `experimental/SkiaExamples/Tutorial.cpp` within the Skia tree.  Copy the following code:
+
+~~~~
+
+#include "SkExample.h"
+#include "SkDevice.h"
+
+class HelloTutorial : public SkExample {
+    public:
+        HelloTutorial(SkExampleWindow* window)
+            : SkExample(window)
+        {
+            fName = "Tutorial";  // This is how Skia will find your example.
+
+            fWindow->setupBackend(SkExampleWindow::kGPU_DeviceType);
+           // Another option is the CPU backend:  fWindow->setupBackend(kRaster_DeviceType);
+        }
+
+    protected:
+        virtual void draw(SkCanvas* canvas) SK_OVERRIDE {
+            // Clear background
+            canvas->drawColor(SK_ColorWHITE);
+
+            SkPaint paint;
+            // Draw a message with a nice black paint.
+            paint.setFlags(SkPaint::kAntiAlias_Flag);
+            paint.setColor(SK_ColorBLACK);
+            paint.setTextSize(SkIntToScalar(20));
+
+            static const char message[] = "Hello World!";
+
+            // Translate and draw the text:
+            canvas->save();
+            canvas->translate(SkIntToScalar(50), SkIntToScalar(100));
+            canvas->drawText(message, strlen(message), SkIntToScalar(0), SkIntToScalar(0), paint);
+            canvas->restore();
+
+            // If you ever want to do animation. Use the inval method to trigger a redraw.
+            this->fWindow->inval(NULL);
+        }
+};
+
+static SkExample* MyFactory(SkExampleWindow* window) {
+    return new HelloTutorial(window);
+}
+static SkExample::Registry registry(MyFactory);
+
+~~~~
+
+
+Step 4: Compile and run SkiaExamples with your Sample
+-----------------------------------------------------
+
+Here is what you have to do to compile your example. There will be
+functionality to make this easier, but for now, this is what you have to do:
+  * Open `gyp/experimental.gyp` and look for the `SkiaExamples` target.
+  * In the 'sources' section of the SkiaExampels target, add
+    `../experimental/SkiaExamples/Tutorial.cpp` to the list of sources.
+  * Repeat Step 2 to update our gyp targets and build our example.
+  * Run the SkiaExamples, specifying the name of our new example: `$> out/Release/SkiaExamples --match Tutorial`
+
+Step 5: How to iterate through multiple examples
+------------------------------------------------
+
+If you did not specify an example with the --match flag, or if your match
+string matches more than one example, you can use the *n* key to iterate
+through all of the examples registered.
+