Moved TimeSheetUtils to shared package.
Created MonthSummaryFragment to replace MonthOverviewFragment.

The month summary displays a list with only the total amount of hours spent for each project. The footer of the list also displays the total amount of hours for the entire month.
Removed unused month overview fragment.

Sadly, the table layout did not work nicely on mobile. Next time, think before you code, @smuldr!
Created view pager structure for switching between months.
Renamed fragment_week_pager.xml to view_pager.xml.

More generic name to reflect generic contents.
Added button to approve monthly data.

- Created options menu for the month summary with approve button
- Created ApproveTask to perform the request on a background thread.
- The approve button is only shown when the month is not stored in Afas yet.
Show lock icon for unchangeable days.

The lock image is slightly less ugly than the original text label.
Improved title format for month summaries.

The title format for the month summaries now uses the best date pattern for the phone's locale, just like the week overview list.
Trim input from edit text views.
Hide duplicate time sheet descriptions.

XTime returns incorrect descriptions for months that are already approved. The description is always equal to the work type description in that case. The parser now filters out these duplicate descriptions.
Renamed WeekOverview to XTimeOverview.

The XTime overview format is also used for the month overview. The class was renamed to avoid confusion.