added -m and -c options

tmp/todo

@@ -0,0 +1,75 @@
+a = a + x ==> a+=x
+
+*******
+
+join consecutive var statements
+
+*******
+
+x == false ==> x == 0
+x == true  ==> x == 1
+
+should warn too;
+JS is so sloppy that this could be an indication of a bug.
+
+*******
+
+x, x ==> x
+x = foo, x ==> x
+
+other similar cases?
+
+*******
+
+Try to concatenate all scripts somehow before starting minification;
+the issue will be keeping track of the current source file for
+generating source maps.  perhaps store that in the AST?  Have a single
+AST_Toplevel for all files.
+
+XXX?  Not sure if this is worth the trouble.
+
+*******
+
+discard spurious break statements
+
+*******
+
+for (...) {
+  if (foo) continue;
+  ...
+}
+
+==>
+
+for (...) {
+  if (!foo) { ... }
+}
+
+*******
+
+The following seems to compress suboptimally.  Should probably run more
+passes somewhere.
+
+function setOpacity(el, o) {
+    if (o != null) {
+        if (o == "" && o != 0) {
+            is_ie
+                ? el.style.filter = ""
+                : el.style.opacity = "";
+        } else {
+            is_ie
+                ? el.style.filter = "alpha(opacity=" + Math.round(o * 100) + ")"
+                : el.style.opacity = o;
+        }
+        return o;
+    } else {
+        if (!is_ie)
+            return parseFloat(el.style.opacity);
+        else
+            if (/alpha\(opacity=([0-9.])+\)/.test(el.style.opacity))
+                return parseFloat(RegExp.$1);
+    }
+}
+
+*******
+