Cleaned up a number of small tweaks in the scripts

- Added the littlefs license note to the scripts.

- Adopted parse_intermixed_args everywhere for more consistent arg
  handling.

- Removed argparse's implicit help text formatting as it does not
  work with perse_intermixed_args and breaks sometimes.

- Used string concatenation for argparse everywhere, uses backslashed
  line continuations only works with argparse because it strips
  redundant whitespace.

- Consistent argparse formatting.

- Consistent openio mode handling.

- Consistent color argument handling.

- Adopted functools.lru_cache in tracebd.py.

- Moved unicode printing behind --subscripts in traceby.py, making all
  scripts ascii by default.

- Renamed pretty_asserts.py -> prettyasserts.py.

- Renamed struct.py -> struct_.py, the original name conflicts with
  Python's built in struct module in horrible ways.

Makefile

@@ -133,7 +133,7 @@ stack: $(CI)
 
 .PHONY: struct
 struct: $(OBJ)
-	./scripts/struct.py $^ -S $(STRUCTFLAGS)
+	./scripts/struct_.py $^ -S $(STRUCTFLAGS)
 
 .PHONY: coverage
 coverage: $(GCDA)
@@ -171,7 +171,7 @@ $(BUILDDIR)lfs.stack.csv: $(CI)
 	./scripts/stack.py $^ -q $(CODEFLAGS) -o $@
 
 $(BUILDDIR)lfs.struct.csv: $(OBJ)
-	./scripts/struct.py $^ -q $(CODEFLAGS) -o $@
+	./scripts/struct_.py $^ -q $(CODEFLAGS) -o $@
 
 $(BUILDDIR)lfs.coverage.csv: $(GCDA)
 	./scripts/coverage.py $^ -q $(COVERAGEFLAGS) -o $@
@@ -195,10 +195,10 @@ $(BUILDDIR)%.s: %.c
 	$(CC) -S $(CFLAGS) $< -o $@
 
 $(BUILDDIR)%.a.c: %.c
-	./scripts/pretty_asserts.py -p LFS_ASSERT $< -o $@
+	./scripts/prettyasserts.py -p LFS_ASSERT $< -o $@
 
 $(BUILDDIR)%.a.c: $(BUILDDIR)%.c
-	./scripts/pretty_asserts.py -p LFS_ASSERT $< -o $@
+	./scripts/prettyasserts.py -p LFS_ASSERT $< -o $@
 
 $(BUILDDIR)%.t.c: %.toml
 	./scripts/test.py -c $< $(TESTCFLAGS) -o $@