Little Go 4+

This is the Little Go bugfix release 1.7.1. It contains two fixes for bugs that caused the app to crash (#397 and #398).

The previous release was the Little Go feature release 1.7.0. An overview of the changes follows, for more details read the in-game Changelog.

Features
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- The app now supports reading and writing of all SGF node annotation and move annotation properties (#339). The app also displays these properties' values and lets you edit them. This means that you can now add a valuation to a move (e.g. good/bad move) and/or to the entire board position (e.g. good position for black/white), designate a board position to be a "hotspot" (e.g. it contains a game-deciding move), annotate a board position with an estimated score, and finally you can add textual notes to a board position. Annotation data is displayed by, and can be edited via, an all-new annotation view.
- The app now supports reading and writing of all SGF markup properties (#349). Except for the DD property (dim parts of the board), the app also displays these properties' values and lets you edit them. This means that you can now mark intersections on the board with 5 different symbols (circle, square, triangle, "X" mark, "selected" symbol), place single-character letter markers or single-digit number markers, place a free-form label text, and finally you can draw arrows or plain lines on the board. The app has an all-new markup editing mode for this (accessible via menu icon) that includes drag & drop support to move around existing markup.
- In the Settings screen there are now a number of user preferences that affect how markup is drawn and that let you tweak some aspects of the markup editing process.

Improvements and changes
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- The general user interface (UI) of Little Go now looks and behaves the same on all device types (#371). This unification of UI layouts became necessary because the effort to support different layouts proved to be too much. Also the unification provided the opportunity to get rid of many behind-the-scenes hacks. The main changes are: 1) Smaller iPhone devices which only support the Portrait orientation UI layout, now display board positions and the navigation buttons differently than before. 2) Larger iPhone devices now display a tab bar when in Landscape orientation (alas, reducing the size of the board). 3) iPad devices now always show board positions when in Portrait orientation, and when in Landscape orientation they display board positions and navigation buttons differently than before.
- Changed the icon of the "More Game Actions" button (#377). The previous icon was a "curved arrow" symbol, which seemed to confuse many users so that they couldn't find important actions, such as "New game". The new icon is the established "hamburger menu" icon, which should now more clearly indicate that the button pops up a menu with actions to select from.
- Button boxes and the board position list now support Dark mode by switching to a dark background color (#378 and #379). Thanks to Peter Waldispühl for reporting this.
- For more improvements/changes see the Changelog.

Bugfixes
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- Board position zero (representing the start of the game) sometimes did not display handicap and komi. This is now fixed (#374).
- Various speculative fixes for potential app crashes. See the Changelog for details.

Regressions
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- A bug was introduced in version 1.6.0 that would cause Ko detection to fail after the app was suspended and was forced to restart by the operating system (a relatively common occurrence). This is now fixed (#372). Because Little Go has struggled with Ko detection many times in the past, this regression was particularly painful.

Technical changes
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- See Changelog.