Change lualatex to xelatex because of incompatibility with xeCJK

Fix for the following error

! Critical Package xeCJK Error: The xeCJK package requires XeTeX to function.
(xeCJK)                         
(xeCJK)                         You must change your typesetting engine to
(xeCJK)                         "xelatex"
(xeCJK)                         instead of plain "latex" or "pdflatex" or
(xeCJK)                         "lualatex".
(xeCJK)                         Loading xeCJK will abort!

Author: ravijo

Makefile

@@ -1,7 +1,7 @@
 # ===========================
 # Configuration
 # ===========================
-CC  := lualatex
+CC  := xelatex
 BIB := biber
 
 EXAMPLES_DIR := examples
@@ -68,4 +68,4 @@ draft:
 draft-clean:
 	@if [ -d $(DRAFT_DIR) ] && [ -f $(DRAFT_DIR)/Makefile ]; then \
 		$(MAKE) -C $(DRAFT_DIR) clean; \
-	fi
+	fi