replace b by strong for semantic, more change in boilerplate

IPython/frontend/html/notebook/static/css/boilerplate.css

@@ -70,10 +70,5 b' select, input, textarea, button { font:99% sans-serif; }'
    en.wikipedia.org/wiki/MediaWiki_talk:Common.css/Archive_11#Teletype_style_fix_for_Chrome */
 pre, code, kbd, samp { font-family: monospace, sans-serif; }
 
-i {
-    font-variant: italic;
-}
-
-b {
-    font-weight:bold;
-}
+em,i { font-style: italic; }
+b,strong { font-weight: bold; }

IPython/frontend/html/notebook/templates/projectdashboard.html

@@ -33,7 +33,7 b' data-read-only={{read_only}}'
         <div id="notebook_toolbar">
             <form id='alternate_upload'  class='alternate_upload' >
                 <span id="drag_info" style="position:absolute" >Drag files
-                    onto the list, or <b>click here</b>, to import
+                    onto the list, or <strong>click here</strong>, to import
                     notebooks.</span>
                 <input type="file" name="datafile" class="fileinput" multiple='multiple'>
             </form>