Fix printing order

[kanunnykov]

Fixes issues #2 and #8

Balanced list of b branch is mixed,
because b.append(..) is used.
b.insert(0, ..) should be used instead.

This code:

from pptree import *

shame = Node("shame")

conscience = Node("conscience", shame)
selfdisgust = Node("selfdisgust", shame)
embarrassment = Node("embarrassment", shame)

selfconsciousness = Node("selfconsciousness", embarrassment)
shamefacedness = Node("shamefacedness", embarrassment)
chagrin = Node("chagrin", embarrassment)
discomfiture = Node("discomfiture", embarrassment)
abashment = Node("abashment", embarrassment)
confusion = Node("confusion", embarrassment)
  
print_tree(shame, horizontal=False)

Currently prints:

 shame                                                                                     
conscience   selfdisgust                                             embarrassment                               
                              selfconsciousness   shamefacedness   chagrin   confusion   abashment   discomfiture

But it should do:

 shame                                                                                     
conscience   selfdisgust                                             embarrassment                               
                              selfconsciousness   shamefacedness   chagrin   discomfiture   abashment   confusion

[kanunnykov]

Also this line in balanced_branches changes the order:
a = sorted(children(current_node), key=lambda node: nb_children(node))

The order will stay the same as user defined, if you change it to:
a = children(current_node)

It seems that it works fine without this sorting.

[kanunnykov]

@clemtoy What do you think about my previous comment? Are there any reasons to change the order specified by client/user/developer? The balancing itself can be done without reordering/sorting.

[ChestnutHeng]

do good job!

[sowmith1729]

@kanunnykov Thanks for the suggestion, It worked for me.

[HuangDell]

Good job! Thanks for your code!