tweaks to icons defaults and in buttons improve vertical align

docs/assets/css/bootstrap.css

@@ -2162,8 +2162,9 @@ table th[class*="span"],
 }
 
 [class^="glyphicon-"]:before {
-  display: inline-block;
-  font: normal 12px/1 'Glyphicons Halflings';
+  font-family: 'Glyphicons Halflings';
+  font-style: normal;
+  line-height: 1;
 }
 
 .glyphicon-glass:before {
@@ -3237,16 +3238,13 @@ button.close {
           border-radius: 3px;
 }
 
-.btn-large [class^="glyphicon-"]::before {
-  font-size: 14px;
-}
-
-.btn-small [class^="glyphicon-"]::before {
-  font-size: 10px;
+.btn [class^="glyphicon-"]::before {
+  vertical-align: -2px;
 }
 
+.btn-small [class^="glyphicon-"]::before,
 .btn-mini [class^="glyphicon-"]::before {
-  font-size: 9px;
+  vertical-align: -1px;
 }
 
 .btn-block {

less/buttons.less

@@ -95,9 +95,9 @@
 // Icons in buttons
 // -------------------------
 
-.btn-large [class^="glyphicon-"]::before { font-size: 14px; }
-.btn-small [class^="glyphicon-"]::before { font-size: 10px; }
-.btn-mini [class^="glyphicon-"]::before  { font-size: 9px; }
+.btn [class^="glyphicon-"]::before       { vertical-align: -2px; }
+.btn-small [class^="glyphicon-"]::before,
+.btn-mini [class^="glyphicon-"]::before  { vertical-align: -1px; }
 
 
 // Block button

less/glyphicons.less

@@ -32,8 +32,9 @@
 
 // Catchall baseclass
 [class^="glyphicon-"]:before {
-  display: inline-block;
-  font: normal 12px/1 'Glyphicons Halflings';
+  font-family: 'Glyphicons Halflings';
+  font-style: normal;
+  line-height: 1;
 }
 
 // Individual icons