Monthly numbers and moved Settings

Changes

• The "Settings" are now not a separate tab anymore, but can be accessed by the header menu (the three dots on the top right). This saves space and is more idiomatic.
• The CSV export now contains two columns for the time: one for the date and one for the time of day. Don't be confused: the time is in UTC, so importing and exporting is time-zone safe, but times may be off by a few hours, depending on your location.
• The CSV export also contains two columns for the category now: one for the original category name, and one for the adapted category.

Features

• In the "Stats" on the very bottom, you can now see monthly summaries for the specific categories, as well as totals. In parentheses, you can see the difference to the prior month.
• When you change a category icon, there's now a search field with some proper search styling.
• The "delete" confirmation dialog now looks a bit cleaner.

Fixes

• Exporting (and importing) now works with Android 7.