Fix: preferences summaries won't be changed

The preferences summary is fixed to be the first entry of list preferences. This pull request will fix this issue. The code is modified from the Setting Activity template.
These two lines should place before the
```
 findPreference(KEY_PREF_OPEN_SOURCE_LICENSES).setOnPreferenceClickListener(this);
```

Steal from Google Java Style:
What is important is that each class order its members in some logical order, which its maintainer could explain if asked. For example, new methods are not just habitually added to the end of the class, as that would yield "chronological by date added" ordering, which is not a logical ordering.

The same to `sBindPreferenceSummaryToValueListener` and `bindPreferenceSummaryToValue`.