support Raspberry Pi Raspbian configure.sh

Raspberry Pi Test Image : 2014-09-09-wheezy-raspbian.img

Test without HDMI/VideoOut/UPnp and 12345 port forwarding throught a firewall.

```
$ uname -a
Linux raspberrypi 3.12.28+ #709 PREEMPT Mon Sep 8 15:28:00 BST 2014 armv6l GNU/Linux
$ cat /etc/os-release
PRETTY_NAME="Raspbian GNU/Linux 7 (wheezy)"
NAME="Raspbian GNU/Linux"
VERSION_ID="7"
VERSION="7 (wheezy)"
ID=raspbian
ID_LIKE=debian
ANSI_COLOR="1;31"
HOME_URL="http://www.raspbian.org/"
SUPPORT_URL="http://www.raspbian.org/RaspbianForums"
BUG_REPORT_URL="http://www.raspbian.org/RaspbianBugs"
$ sudo apt-get update
$ sudo apt-get -y install git curl wget python
$ git clone --depth 1 --branch master https://github.com/OpenBazaar/OpenBazaar
$ cd OpenBazaar
$ ./configure.sh
.... wait 2~3 hours ...
$ IP=$(/sbin/ifconfig eth0 | grep 'inet addr:' | cut -d: -f2 | awk '{ print $1}')
$ ./run.sh -j --disable-open-browser -k $IP -q 8888 -p 12345; tail -f logs/production.log
```

ref  #596 
> it's ok to default Y still

 'Are you sure? [Y/n]' may not survive the incautious and over-eager ENTERs.