Add watch target to Makefile

Automatically rebuild whenever a .tex file is changed. Use with make watch. Useful when you write in a native environment (i.e. not ShareLatex or similar) and use make a lot in the terminal. make knows what files have been edited since the last time it run, therefore make watch will not do anything between edits.

Makefile

@@ -24,6 +24,9 @@ $(PDFNAME).pdf: $(TEXMAINFILE) *.tex
 view: $(PDFNAME).pdf
 	$(PDFVIEWER) $(PDFNAME).pdf &
 
+watch:
+	while true; do make --silent; sleep 2; done
+
 clean:
 	$(MKLATEX) -CA
 	rm -f $(PDFNAME).pdf *.{aux,bbl,bcf,blg,cb,fdb_latexmk,fls,lof,log,lot,out,run.xml,rel,synctex.gz,toc}