Various bug fixes and small features (#606)

* Fix stray cursor, integer overflows and other bugs

* check for getenvlist error, shorten code

* fix cascade, set info_line before auth, make code clearer and a bug fix

* Add option to turn on numlock at startup

* Fix setting numlock

* Update build.zig

* Custom info text

* Shift+Tab for previous input

* update changelog and res/config

* Some fixes

* update build.zig

* update build.zig again

* Fix xauth command for some shells and fix building in ReleaseSafe

* Use git describe to get dev version str

* revert change to getLockState (it broke the doom animation)

* add new ly error messages. Only try to make path for pam/exe during install when dest_directory is defined + print warning on error.

* add warning message for workaround

src/animations/Doom.zig

@@ -56,7 +56,7 @@ pub fn draw(self: Doom) void {
             const source = y * self.terminal_buffer.width + x;
             const random = (self.terminal_buffer.random.int(u16) % 7) & 3;
 
-            var dest = source - random + 1;
+            var dest = (source - @min(source, random)) + 1;
             if (self.terminal_buffer.width > dest) dest = 0 else dest -= self.terminal_buffer.width;
 
             const buffer_source = self.buffer[source];