Made errors a little more helpful

Also, Hide stack traces when error message provided

app/src/processing/app/contrib/ContributionManager.java

@@ -102,7 +102,8 @@ public class ContributionManager {
     } catch (IOException ioe) {
       if (progress != null)
         progress.error(ioe);
-      ioe.printStackTrace();
+      // Hiding stack trace. An error has been shown where needed. 
+//      ioe.printStackTrace();
     }
     if (progress != null)
       progress.finished();
@@ -155,11 +156,26 @@ public class ContributionManager {
               }
               installProgress.finished();
             }
+            else {
+              if (downloadProgress.exception instanceof SocketTimeoutException) {
+                status.setErrorMessage(Language
+                  .interpolate("contrib.errors.contrib_download.timeout",
+                               ad.getName()));
+              } else {
+                status.setErrorMessage(Language
+                  .interpolate("contrib.errors.download_and_install",
+                               ad.getName()));
+              }
+            }
             contribZip.delete();
 
           } catch (Exception e) {
-            e.printStackTrace();
-            status.setErrorMessage(Language.text("contrib.errors.download_and_install"));
+            // Hiding stack trace. The error message ought to suffice.
+//            e.printStackTrace();
+            status
+              .setErrorMessage(Language
+                .interpolate("contrib.errors.download_and_install",
+                             ad.getName()));
           }
         } catch (IOException e) {
           status.setErrorMessage(Language.text("contrib.errors.temporary_directory"));

app/src/processing/app/contrib/ContributionManagerDialog.java

@@ -411,7 +411,6 @@ public class ContributionManagerDialog {
     }
   }
 
-  
   protected void setFilterText(String filter) {
     if (filter == null || filter.isEmpty()) {
       filterField.setText("");

app/src/processing/app/languages/PDE.properties

@@ -269,15 +269,17 @@ contrib.messages.install_restart = Please restart Processing to finish installin
 contrib.messages.update_restart = Please restart Processing to finish updating this item.
 contrib.errors.list_download = Could not download the list of available contributions.
 contrib.errors.list_download.timeout = Connection timed out while downloading the contribution list.
-contrib.errors.download_and_install = Error during download and install.
+contrib.errors.download_and_install = Error during download and install of %s.
 contrib.errors.description_unavailable = Description unavailable.
-contrib.errors.malformed_url = "The link fetched from Processing.org is not valid.\nYou can still install this library manually by visiting\nthe library's website.
+contrib.errors.malformed_url = The link fetched from Processing.org is not valid.\nYou can still install this library manually by visiting\nthe library's website.
 contrib.errors.needs_repackage = %s needs to be repackaged according to the %s guidelines.
 contrib.errors.no_contribution_found = Could not find a %s in the downloaded file.
 contrib.errors.overwriting_properties = Error overwriting .properties file.
 contrib.errors.install_failed = Install failed.
 contrib.errors.update_on_restart_failed = Update on restart of %s failed.
 contrib.errors.temporary_directory = Could not write to temporary directory.
+contrib.errors.contrib_download.timeout = Connection timed out while downloading %s.
+contrib.errors.no_internet_connection = You don't seem to be connected to the Internet.
 contrib.all = All
 contrib.undo = Undo
 contrib.remove = Remove