Import the JS API specification. (#88)

* [js-api] Import upstream specification.

Source: WebAssembly/spec@666dc4c

* [js-api] Import reference-types changes.

Source: WebAssembly/reference-types@aa596e5

* [js-api] Link to reference-types proposal.

document/js-api/Makefile

@@ -0,0 +1,44 @@
+BUILDDIR      = _build
+STATICDIR     = _static
+DOWNLOADDIR   = _download
+NAME          = WebAssembly
+
+.PHONY: all
+all:
+	mkdir -p $(BUILDDIR)/html
+	bikeshed spec index.bs $(BUILDDIR)/html/index.html
+	@echo "Build finished. The HTML pages are in `pwd`/$(BUILDDIR)/html."
+
+.PHONY: publish
+publish:
+	(cd ..; make publish-js-api)
+
+.PHONY: clean
+clean:
+	rm -rf $(BUILDDIR)
+	rm -rf $(STATICDIR)
+
+.PHONY: diff
+diff: all
+	@echo "Downloading the old single-file html spec..."
+	curl `grep "^TR" index.bs | cut -d' ' -f2` -o $(BUILDDIR)/html/old.html
+	@echo "Done."
+	@echo "Diffing new against old..."
+	perl ../util/htmldiff.pl $(BUILDDIR)/html/old.html $(BUILDDIR)/html/index.html $(BUILDDIR)/html/diff.html
+	@echo "Done. The diff is at $(BUILDDIR)/html/diff.html"
+
+.PHONY: WD-tar
+WD-tar:
+	bikeshed echidna --just-tar index.bs $(BUILDDIR)/html/index.html
+	mv test.tar $(BUILDDIR)/WD.tar
+	@echo "Built $(BUILDDIR)/WD.tar."
+
+.PHONY: WD-echidna
+WD-echidna:
+	@if [ -z $(W3C_USERNAME) ] || \
+	    [ -z $(W3C_PASSWORD) ] || \
+			[ -z $(DECISION_URL) ] ; then \
+		echo "Must provide W3C_USERNAME, W3C_PASSWORD, and DECISION_URL environment variables"; \
+		exit 1; \
+	fi
+	bikeshed echidna index.bs --u $(W3C_USERNAME) --p $(W3C_PASSWORD) --d $(DECISION_URL)