Fix is_combining_mark table data

* In `scripts/unicode.py`, the data used to generate `is_combining_mark()`
was being passed to the emit function incorrectly, resulting in the
table containing some other data instead. The script is fixed and new
`tables.rs` is generated.

* Add test for `is_combining_mark()` for ASCII chars, as well as a
couple of random chars based on the reported issue.

Fix #16

Author: behnam

scripts/unicode.py

@@ -350,7 +350,7 @@ def comp_vfun(char):
 
 """)
 
-    emit_table(f, "general_category_mark", combine, "&'static [(char, char)]", is_pub=False,
+    emit_table(f, "general_category_mark", general_category_mark, "&'static [(char, char)]", is_pub=False,
             pfun=lambda x: "(%s,%s)" % (escape_char(x[0]), escape_char(x[1])))
 
     f.write("""