Rename vram to vip internally

src/memory.rs

@@ -263,7 +263,7 @@ impl MemoryRegion {
         /*
          * We have four buffers, and (at time of writing) only three threads interacting with memory:
          * - The UI thread, reading small regions of memory
-         * - The "vram renderer" thread, reading large regions of memory
+         * - The "image renderer" thread, reading large regions of memory
          * - The emulation thread, writing memory every so often
          * So it should be impossible for all four buffers to have a read lock at the same time,
          *  and (because readers always read the newest buffer) at least one of the oldest three