makefile, actually output to `src/` folder

Makefile

 FILES := \
-  HsH-article.cls \
-  HsH-report.cls \
-  HsH-standalone.cls \
-  config.tex
+  src/HsH-article.cls \
+  src/HsH-report.cls \
+  src/HsH-standalone.cls \
+  src/config.tex
 
 .PHONY: src
 src: $(FILES)
 $(FILES) &: HsH-Classes.ins HsH-Classes.dtx
-	latex HsH-Classes.ins
+	latex -output-directory=src HsH-Classes.ins
 
 .PHONY: clean
 clean: