Typography fix

Deprecated the use of Arial in favor of Monaco, one of the top 10
preferred fonts for coding present in every OSX. If not present, then
will come Helvetica, then any sans the OS wants.

css/amber.css

@@ -225,7 +225,7 @@ body.jtalkBody {
 .jtalkTool textarea,
 .jtalkTool input {
     border: 0 none;
-    font-family: Arial, Helvetica, sans;
+    font-family: Monaco, Helvetica, sans;
     line-height: 1.3em;
     font-size: 12px;
     position: relative;
@@ -234,7 +234,7 @@ body.jtalkBody {
 
 .jtalkTool .CodeMirror {
     border: 0 none;
-    font-family: Arial, Helvetica, sans;
+    font-family: Monaco, Helvetica, sans;
     font-size: 12px;
     line-height: 1.3em;
     height: 100%;
@@ -246,7 +246,7 @@ body.jtalkBody {
 }
 
 .talkTool .CodeMirror-scroll pre {
-    font-family: Arial, Helvetica, sans;
+    font-family: Monaco, Helvetica, sans;
 }
 
 .jtalkTool .jt_clear {