Fixed * and / operators to prioritize over + and -.

tests/debug.jet

@@ -0,0 +1,5 @@
+#!../jet-2.0
+<jet name1="localname" filterblanklines="true" trimlines="true">
+<set name="result" expr="2 + 2 * 3 + 2" />
+$[result]=10
+</jet>

tests/testexpr.jet

@@ -12,4 +12,12 @@ $[righty]=56789
 $[trim]=this is a test
 <set name="integer" expr="integer(12430.54356546)" />
 $[integer]=12430
+<set name="result" expr="5 + 5 * 5" />
+$[result]=30
+<set name="result" expr="5 + 5 * 5 + 5" />
+$[result]=35
+<set name="result" expr="(5 * 2) + (5 * 5) + (5 * 2)" />
+$[result]=45
+<set name="result" expr="2 + 2 * 3 + 2" />
+$[result]=10
 </jet>