Renames the assembler* files.

Renames the assembler* files to IceAssembler*. Fixes whatever breaks.

BUG= https://code.google.com/p/nativeclient/issues/detail?id=4077
R=jvoung@chromium.org

Review URL: https://codereview.chromium.org/1179563004.
diff --git a/src/IceCfg.h b/src/IceCfg.h
index 056812b..c231860 100644
--- a/src/IceCfg.h
+++ b/src/IceCfg.h
@@ -15,7 +15,7 @@
 #ifndef SUBZERO_SRC_ICECFG_H
 #define SUBZERO_SRC_ICECFG_H
 
-#include "assembler.h"
+#include "IceAssembler.h"
 #include "IceClFlags.h"
 #include "IceDefs.h"
 #include "IceGlobalContext.h"