replace isNewWord and isUpperCase functions with regexes

Slight speedup, actually less than I thought, but my benchmarks
are limited.  Normally, I'm all about readability and make functions
that I only use once to make the code more readable, but this is an
algorithm that needs to be fast, and the regexes are very simple.

Also, may catch some more cases, as `\s` will match other space chars
than just ' ' and '\t' would.

liquidmetal.js

@@ -18,7 +18,7 @@ var LiquidMetal = (function() {
   var SCORE_TRAILING = 0.8;
   var SCORE_TRAILING_BUT_STARTED = 0.9;
   var SCORE_BUFFER = 0.85;
-
+  
   return {
     score: function(string, abbreviation) {
       // Short circuits
@@ -50,20 +50,21 @@ var LiquidMetal = (function() {
         c = chars[i];
         index = lower.indexOf(c, lastIndex+1);
 
-        if (index === -1)  return false; // signal no match
+        if (index === -1)  return false; // return no match
 
         if (index === 0) started = true;
-
-        if (isNewWord(string, index)) {
+
+        // is new word:
+        if ( /\s/.test( string.charAt(index-1) ) ) {
           scores[index-1] = 1;
           fillArray(scores, SCORE_BUFFER, lastIndex+1, index-1);
         }
-        else if (isUpperCase(string, index)) {
+        // is upper:
+        else if ( /[A-Z]/.test( string.charAt(index) ) )
           fillArray(scores, SCORE_BUFFER, lastIndex+1, index);
-        }
-        else {
+
+        else
           fillArray(scores, SCORE_NO_MATCH, lastIndex+1, index);
-        }
 
         scores[index] = SCORE_MATCH;
         lastIndex = index;
@@ -74,16 +75,6 @@ var LiquidMetal = (function() {
       return scores;
     }
   };
-
-  function isUpperCase(string, index) {
-    var c = string.charAt(index);
-    return ("A" <= c && c <= "Z");
-  }
-
-   function isNewWord(string, index) {
-    var c = string.charAt(index-1);
-    return (c == " " || c == "\t");
-  }
 
   function fillArray(array, value, from, to) {
     for (var i = from; i < to; i++) { array[i] = value; }