replaced some icons from the presentation module by the google's material design icons

bigbluebutton-client/branding/default/style/css/BBBDefault.css

@@ -270,23 +270,23 @@ DataGrid {
 }
 
 .presentationUploadButtonStyle {
-  icon:   Embed('assets/images/upload.png');   
+  icon:   Embed('assets/images/ic_file_upload_16px.png');
 }
 
 .presentationBackButtonStyle {
-  icon:   Embed('assets/images/left-arrow.png'); 
+  icon:   Embed('assets/images/ic_arrow_back_24px.png');
 }
 
 .presentationBackButtonDisabledStyle {
-	icon:   Embed('assets/images/left-arrow-disabled.png'); 
+	icon:   Embed('assets/images/ic_arrow_back_grey_24px.png');
 }
 
 .presentationForwardButtonStyle {
-  icon:   Embed('assets/images/right-arrow.png'); 
+  icon:   Embed('assets/images/ic_arrow_forward_24px.png');
 }
 
 .presentationForwardButtonDisabledStyle {
-	icon:   Embed('assets/images/right-arrow-disabled.png'); 
+	icon:   Embed('assets/images/ic_arrow_forward_grey_24px.png');
 }
 
 .presentationFitToWidthButtonStyle {
@@ -298,7 +298,7 @@ DataGrid {
 }
 
 .presentationDownloadButtonStyle {
-  icon:   Embed('assets/images/disk.png'); 
+  icon:   Embed('assets/images/ic_file_download_16px.png');
 }
 
 .presentationZoomSliderStyle{
@@ -855,4 +855,4 @@ Alert {
 .statusMessageStyle {
   fontSize: 12;
   paddingTop: 0;
-}
+}

bigbluebutton-client/src/org/bigbluebutton/modules/present/ui/views/PresentationWindow.mxml

@@ -625,10 +625,10 @@ with BigBlueButton; if not, see <http://www.gnu.org/licenses/>.
 	<views:SlideView id="slideView" width="100%" height="100%" visible="false" mouseDown="mouseDown = true"
 		mouseUp="mouseDown = false" verticalScrollPolicy="off" horizontalScrollPolicy="off" tabIndex="{baseIndex+4}"/>			    
 	<mx:ControlBar id="presCtrlBar" name="presCtrlBar" width="100%" height="{CONTROL_BAR_HEIGHT}" styleName="presentationWindowControlsStyle" >
-		<mx:Button id="downloadPres" visible="true" height="30" styleName="presentationDownloadButtonStyle"
+		<mx:Button id="downloadPres" visible="true" height="30" width="30" styleName="presentationDownloadButtonStyle"
     		toolTip="{ResourceUtil.getInstance().getString('bbb.presentation.downloadPresBtn.toolTip')}" 
     	   	click="onDownloadButtonClicked()" tabIndex="{baseIndex+5}"/> 	
-		<mx:Button id="uploadPres" visible="false" height="30" styleName="presentationUploadButtonStyle"
+		<mx:Button id="uploadPres" visible="false" height="30" width="30" styleName="presentationUploadButtonStyle"
     		toolTip="{ResourceUtil.getInstance().getString('bbb.presentation.uploadPresBtn.toolTip')}" 
     	   	click="onUploadButtonClicked()" tabIndex="{baseIndex+5}"/>        	  
     	<mx:Spacer width="100%" id="spacer1"/>