Bugfixes

- Scrolling feature in Add/Edit New Source Screen
- Prevent duplicate Sources in multiple-source gifts. New/Edit Source screen.
- All gifts Screen should only display gifts in the chosen year and not other years.
- Negative limit should have an explicit minus sign before it.
- Source details screen: gift value should add up to the total received field. In other words, only display the portion that the source contributed, not the total value of gift.
- Default email message should say iOS instead of Android