major usability improvements

Terminal now modal, supports line buffering, stdin, because it uses pty (and threading). Also supports paste, again (?). Audio player queueing no longer blocks, supports appending. Now can change window size. Halfscreen window shortcut improved. Eliminate dirs dep, deconstruct audiotags dep, better feature flags. Remove .alpha files because they are built. Use /home/jondough for default dirs if possible. Themes config. Fix for rotated touchscreen. Write more docs

docs/window-likes/audio-player.md

@@ -8,8 +8,9 @@ Type to write commands, backspace to delete last character, and enter to run com
 - `l`: Next/skip
 - `j`: Volume down
 - `k`: Volume up
-- `b <dir>`: Set base directory (`<dir>` is path)
+- `b <dir>`: Set base directory (`<dir>` is path). Unless paths are absolute, they will be relative to what the base directory currently is (by default, `$HOME` is set, `/` otherwise)
 - `p <dir / playlist file>`: Play audio files in `<dir>` or play the songs listed in the `<playlist file>`. Unless paths are absolute, they will be relative to the directory specified by the `b <dir>` command
+- `a <dir / playlist file>`: Same as `p` but appends to the end of the queue instead of clearing the current song and the queue
 
 ## Playlists
 
@@ -19,5 +20,8 @@ Example playlist file:
 hanyuu-maigo/オノマトペ
 inabakumori/*
 iyowa/*
-kai/さよならプリンセス
+such/Hegira
 ```
+
+If there is no file extension, the player assumes `.mp3`.
+