[MC-57357] superflatt tryangles

when customising a superflatt world all blocks in the "layer material height" part are all tryangles
it also soesn't render many of the preset icons

Environment

Operating System: Windows 7 (x86) version 6.1
Java Version: 1.7.0_55, Oracle Corporation
Java VM Version: Java HotSpot(TM) Client VM (mixed mode, sharing), Oracle Corporation
Memory: 81564080 bytes (77 MB) / 309723136 bytes (295 MB) up to 518979584 bytes (494 MB)
JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx512M
IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
LWJGL: 2.9.1
OpenGL: AMD Radeon HD 6800 Series GL version 4.3.12618 Compatibility Profile Context 13.251.0.0, ATI Technologies Inc.
GL Caps: Using GL 1.3 multitexturing.