abbreviate bug report

[7c]

i hope this makes the bug clear:

> ip6.abbreviate('::0000:1')
'::1'
> ip6.abbreviate('000::0000:1')
'::1'
> ip6.abbreviate('0000::0000:1')
'::1'
> ip6.abbreviate('1:0000::0000:1')
'0001::1'
> ip6.abbreviate('01:0000::0000:1')
'0001::1'
> ip6.abbreviate('12:0000::0000:1')
'0012::1'
> ip6.abbreviate('123:0000::0000:1')
'0123::1'
> 

[elgs]

@7c thank you so much! This should have been fixed in 0.2.11.