updated issues.md; fixed target cleanimg

Doc/Makefile

@@ -50,4 +50,4 @@ cleansubfoldertex: # {{{
 	-cd $(TEXF); rm $(shell cd $(TEXF); find * | grep -v tex);
 # }}}
 cleanimg:
-	cd $(IMGF)); make clean
+	cd $(IMGF); make clean

issues.md

@@ -2,4 +2,4 @@
 - `mathastext` has to be preceeded by `\usepackage[no-math]{fontspec}`
 
 # MRTsfacc
-- nested use of `\mathaccentV` doesn't work properly
+- (solved) nested use of `\mathaccentV` doesn't work properly