Add Token support for Bugzilla 4.4 and newer
remove ability to set output encoding

This does not work properly under python 3.3, and I was told that there
is no reason we should be allowing it in older versions of python
either.
bugz/cli.py: Use a shell-enabled subprocess for the passwordcmd

Allows correct handling of quoting and pipes in the command.
For convenience, only use the first line of output as password
(assumption: passwords don't contain newlines).
Fix setup url.
Clean up showbuginfo

- Combine the FIELDS and MORE_FIELDS variables
- clean up the exception handling
- make the display code smart enough to use longdesc if it is defined or
  just the field name otherwise.
style fix
Display almost all fields in a bug object

This commit rewrites showbuginfo to display almost every field in a bug
object.

Currently is_open, id, is_confirmed, is_creator_accessible,
and is_cc_accessible are not displayed since they are not displayed on
the web interface. Also, update_token is not displayed for security
reasons.
Drop python 2 support

During testing, I received this backtrace as a result of running
"bugz get 373219 > file.txt" on Gentoo's bugzilla:

Traceback (most recent call last):
  File "/usr/lib/python-exec/python2.7/bugz", line 72, in <module>
    sys.exit(main())
  File "/usr/lib/python-exec/python2.7/bugz", line 47, in main
    args.func(bugz, args)
  File "/usr/lib64/python2.7/site-packages/bugz/cli.py", line 281, in get
    self.showbuginfo(bug, args.attachments, args.comments)
  File "/usr/lib64/python2.7/site-packages/bugz/cli.py", line 775, in showbuginfo
    print line
UnicodeEncodeError: 'ascii' codec can't encode character u'\u0142' in position 7: ordinal not in range(128)

while researching this, I was referred to the following upstream issues:

https://bugs.python.org/issue6832
https://bugs.python.org/issue14192

This is not going to be fixed in python 2.x, so I am dropping python 2
support.
allow man pages to work properly with virtualenv.
style fix
style fixes

- fix imports

- rename bzcall to call_bz, listbugs to list_bugs and showbuginfo to
  show_bug_info.
Search: add options to show priority and severity

This closes #62.
Remove more references to the keys method
Setup: install man page relative to sys.prefix
increment version
Make --status = ALL case-insensitive
Move default config file to command line parser
do not bail if user configuration file cannot be opened