Revert "Merge pull request #71 from casey/rebuild-makefile"

This reverts commit 443d15017aac19a0d5fe3cdce0d8df745475ed51, reversing
changes made to 1fa0d86ffb850db90d70b257628cbcf230199bc0.
diff --git a/Makefile b/Makefile
deleted file mode 100644
index 43210a9..0000000
--- a/Makefile
+++ /dev/null
@@ -1,5 +0,0 @@
-rebuild-headers:
-	mkdir -p tools/buildHeaders/build
-	cd tools/buildHeaders/build && cmake .. && cmake --build .
-	cd include/spirv/unified1 && \
-		../../../tools/buildHeaders/build/BuildSpvHeaders -H spirv.core.grammar.json