Adopted new tree renderer in dbgmtree, implemented mtree rendering

In addition to plugging in the rbyd and btree renderers in dbgbtree.py,
this required wiring in rbyd trees in the mdirs and mroots.

A bit tricky, but with a more-or-less straightforward implementation thanks
to the common edge description used for the tree renderer.

For example, a relatively small mtree:

  $ ./scripts/dbgmtree.py disk -B4096 -t -i
  mroot 0x{0,1}.45, rev 1, weight 0
  mdir                     ids   tag                     ...
  {0000,0001}: .--------->    -1 magic 8                 ...
               | .------->       config 21               ...
               +-+-+             btree 7                 ...
    0006.000a:     | .-+       0 mdir w1 2               ...
  {0002,0003}:     | | '->   0.0 inlined w1 1024         ...
    0006.000a:     '-+-+       1 mdir w1 2               ...
  {0004,0005}:         '->   1.0 inlined w1 1024         ...

scripts/dbgbtree.py

@@ -367,7 +367,7 @@ class Rbyd:
         id = -1
 
         while True:
-            done, id, tag, w, j, d, data = self.lookup(id, tag+0x10)
+            done, id, tag, w, j, d, data, _ = self.lookup(id, tag+0x10)
             if done:
                 break
 
@@ -628,7 +628,7 @@ def main(disk, roots=None, *,
                             'c': branch['c'],
                         })
 
-                    d_ += max(rdepth, 1)
+                    d_ += max(bdepths.get(d, 0), 1)
                     leaf = (bid-(w-1), d, rid-(w-1), TAG_BTREE)
 
             # remap branches to leaves if we aren't showing inner branches
@@ -679,7 +679,6 @@ def main(disk, roots=None, *,
             tree = []
             root = None
             branches = {}
-            leaves = {}
             bid = -1
             while True:
                 done, bid, w, rbyd, rid, tags, path = btree_lookup(
@@ -741,7 +740,6 @@ def main(disk, roots=None, *,
                 t_width = 2*t_depth + 2
 
             def treerepr(bid, w, bd, rid, tag):
-#                print('%-32s' % repr((bid-(w-1), bd, rid, tag)), end='')
                 if t_depth == 0:
                     return ''
 
@@ -873,6 +871,7 @@ def main(disk, roots=None, *,
             if done:
                 break
 
+            # print inner btree entries if requested
             if args.get('inner'):
                 changed = False
                 for (x, px) in it.zip_longest(
@@ -897,7 +896,6 @@ def main(disk, roots=None, *,
                     '\x1b[31m' if color else '',
                     '(corrupted rbyd %s)' % rbyd.addr(),
                     '\x1b[m' if color else ''))
-
                 prbyd = rbyd
                 corrupted = True
                 continue