Minimize texture binds when drawing text

When several CacheTextures are used to draw text, sort the
draw batches by texture ID to minimize state changes in the
driver.

This change also tweaks the font cache size and renames
a property that was too long to be set using setprop.

Change-Id: I0a36dfffe58c9e75dd7384592d3343c192d042b1
diff --git a/libs/hwui/Properties.h b/libs/hwui/Properties.h
index 5f39abf..e4b4f3c 100644
--- a/libs/hwui/Properties.h
+++ b/libs/hwui/Properties.h
@@ -119,7 +119,7 @@
 #define PROPERTY_FBO_CACHE_SIZE "ro.hwui.fbo_cache_size"
 
 // These properties are defined in percentage (range 0..1)
-#define PROPERTY_TEXTURE_CACHE_FLUSH_RATE "ro.hwui.texture_cache_flush_rate"
+#define PROPERTY_TEXTURE_CACHE_FLUSH_RATE "ro.hwui.texture_cache_flushrate"
 
 // These properties are defined in pixels
 #define PROPERTY_TEXT_SMALL_CACHE_WIDTH "ro.hwui.text_small_cache_width"