Replace ProgressDialog

[SchoolGuy]

While working on #172 I noticed that we have three usages of the class ProgressDialog. This is deprecated since API Level 26.

The "goto" solution is to use a ProgressBar in our layout.

The three usages of ProgressDialog are in:

• https://github.com/cgeo/WhereYouGo/blob/master/src/main/java/menion/android/whereyougo/network/DownloadCartridgeTask.java
• https://github.com/cgeo/WhereYouGo/blob/master/src/main/java/menion/android/whereyougo/openwig/WUI.java
• https://github.com/cgeo/WhereYouGo/blob/master/src/main/java/menion/android/whereyougo/gui/SaveGame.java

Source: https://developer.android.com/reference/android/app/ProgressDialog Also mentioned in: https://developer.android.com/guide/topics/ui/dialogs