Last minute tweaks to debug scripts

- Standardized littlefs debug statements to use hex prefixes and
  brackets for printing pairs.

- Removed the entry behavior for readtree and made -t the default.
  This is because 1. the CTZ skip-list parsing was broken, which is not
  surprising, and 2. the entry parsing was more complicated than useful.
  This functionality may be better implemented as a proper filesystem
  read script, complete with directory tree dumping.

- Changed test.py's --gdb argument to take [init, main, assert],
  this matches the names of the stages in C's startup.

- Added printing of tail to all mdir dumps in readtree/readmdir.

- Added a print for if any mdirs are corrupted in readtree.

- Added debug script side-effects to .gitignore.

.gitignore

@@ -8,3 +8,5 @@ blocks/
 lfs
 test.c
 tests/*.toml.*
+scripts/__pycache__
+.gdb_history