Add smoosh dependencies to Makefile

Setting the SMOOSH variable to the path of the binary allows us a
shorthand reference for use in a rule, listing as a dependency, and even
defining a target.

I've added a target so that if smoosh isn't there, make will actually
trigger NPM.

Then every target that used smoosh was changed over to use the $(SMOOSH)
variable (No more $PATH problem!) and given smoosh as a dependency.

Makefile

@@ -1,36 +1,41 @@
+SMOOSH = ./node_modules/.bin/smoosh
+
 all: test flotr2
 
+$(SMOOSH):
+	npm install
+
 test:
 	cd spec; jasmine-headless-webkit -j jasmine.yml -c
 
-libraries:
-	smoosh make/lib.json
+libraries: $(SMOOSH)
+	$(SMOOSH) make/lib.json
 	cat ./build/bean.js > build/lib.js
 	cat ./build/underscore.js >> build/lib.js
 	cat ./build/bean.min.js > build/lib.min.js
 	echo ";" >> build/lib.min.js
 	cat ./build/underscore.min.js >> build/lib.min.js
 	echo ";" >> build/lib.min.js
 
-ie:
-	smoosh make/ie.json
+ie: $(SMOOSH)
+	$(SMOOSH) make/ie.json
 
-flotr2: libraries ie
-	smoosh make/flotr2.json
+flotr2: libraries ie $(SMOOSH)
+	$(SMOOSH) make/flotr2.json
 	cat build/lib.js build/flotr2.js > flotr2.js
 	cat build/lib.min.js > flotr2.min.js
 	cat build/flotr2.min.js >> flotr2.min.js
 	echo ';' >> flotr2.min.js
 	cp build/ie.min.js flotr2.ie.min.js
 	cat build/flotr2.js > flotr2.nolibs.js
 
-flotr2-basic: libraries ie
-	smoosh make/basic.json
+flotr2-basic: libraries ie $(SMOOSH)
+	$(SMOOSH) make/basic.json
 	cat build/lib.min.js > flotr2-basic.min.js
 	cat build/flotr2-basic.min.js >> flotr2-basic.min.js
 
-flotr-examples:
-	smoosh make/examples.json
+flotr-examples: $(SMOOSH)
+	$(SMOOSH) make/examples.json
 	cp build/examples.min.js flotr2.examples.min.js
 	cp build/examples-types.js flotr2.examples.types.js