Fixed more windows warnings

- Fixed uninitialized variables in default cases
- Fixed truncation of values to float with static_cast

Change-Id: I81f3a243e66eaeb24cd92646c6ef1ca6cb0de9ce
Reviewed-on: https://swiftshader-review.googlesource.com/5682
Tested-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <capn@google.com>

src/Renderer/Renderer.cpp

diff --git a/src/Renderer/Renderer.cpp b/src/Renderer/Renderer.cpp
index b6ce802..d854deb 100644
--- a/src/Renderer/Renderer.cpp
+++ b/src/Renderer/Renderer.cpp
@@ -264,7 +264,9 @@
 					setupPrimitives = &Renderer::setupVertexTriangle;
 					batch = 1;
 					break;
-				default: ASSERT(false);
+				default:
+					ASSERT(false);
+					return;
 				}
 			}
 			else if(context->isDrawLine())