base: ips uses ifconfig or ip according to $OSTYPE, supports IPv6

ifconfig not available to users on Linux and it has a different output,
using ip instead. Also, added support to show IPv6 addresses too.
base: added colornetstat command

Netstat now have colors
history: no history clutter when running under Midnight Commander
browser: plugin now supports opening the files on linux

Original plugin only supported OSX. Now it works on Linux and
some other Unixes too, although still a bit rudimentary.
base.theme: older git support

older Git symbolic-ref command didn't had the --short option
replaced it with a sed call
_xterm: use $PWD instead of dirs -0

I prefer the full path, and it's slightly faster.
That's all
pure-folti: my version of the pure theme
catimg: plugin stolen from oh-my-zsh