Crash related to tag parsing

Occasionally when processing tags, a few things can happen:

Previously entered tags (from the history file) won't appear correctly. Instead of this-tag, it would appear as '## ## #t #h #i #s #- #t #a #g'.
Just hitting enter tends to avoid a crash, but the resulting file will have tags appearing like that.
Attempting to add a tag will usually lead to a crash.

2016-09-09 00:00:00 COFFEE                        2.23
Payee [Coffee]:
Account [Expenses:Food:Coffee]:
Tag [## ## #t #h #i #s #- #t #a #g]: this-tag
Tag [## ## #t #h #i #s #- #t #a #g]:

And the error:

Traceback (most recent call last):
  File "/usr/local/bin/plaid2text", line 6, in <module>
    exec(compile(open(__file__).read(), __file__, 'exec'))
  File ".../plaid2text/bin/plaid2text", line 2, in <module>
    from plaid2text.plaid2text import main;main()
  File ".../plaid2text/src/python/plaid2text/plaid2text.py", line 352, in main
    update_dict = out.process_transactions()
  File ".../plaid2text/src/python/plaid2text/renderers.py", line 166, in process_transactions
    out = self._process_plaid_transactions()
  File ".../plaid2text/src/python/plaid2text/renderers.py", line 180, in _process_plaid_transactions
    payee, account, tags = self.get_payee_and_account(entry)
  File ".../plaid2text/src/python/plaid2text/renderers.py", line 238, in get_payee_and_account
    value = self.prompt_for_tags('Tag', self.possible_tags, tags)
  File ".../plaid2text/src/python/plaid2text/renderers.py", line 395, in prompt_for_tags
    tags.append(value)
AttributeError: 'str' object has no attribute 'append'

Basically it looks like the prompt_for_tags is treating tags as both a string and a list in difference places, which is causing the issue.

I should be able to fix this later, but I wanted to write this up in case you had identified the problem and had done it already.

madhat2r / plaid2text

Crash related to tag parsing #11