gnunet-qr: Update documentation and scripts to changed dependencies.

Requirement python-zbar is gone, and thus the requirement for
Python 2.7. Instead development package for libzbar is required now.

README

@@ -124,6 +124,7 @@ These are the optional dependencies:
 - libogg             >= 1.3.0       (for experimental conversation tool)
 - libnss                            (certtool binary (for convenient
                                      installation of GNS proxy))
+- libzbar            >= 0.10        (for gnunet-qr)
 - libpbc             >= 0.5.14      (for Attribute-Based Encryption and
                                      Identity Provider functionality)
 - libgabe                           (for Attribute-Based Encryption and
@@ -135,7 +136,6 @@ These are the optional dependencies:
 - perl5                             (for some utilities)
 - python2.7          = 2.7          (for gnunet-qr, only python 2.7
                                      supported)
-- python-zbar        >= 0.10        (for gnunet-qr, not optional)
 - TeX Live           >= 2012        (for gnunet-bcd[*])
 - texi2mdoc                         (for automatic mdoc generation [*2])
 

contrib/vagrant/bootstrap.ubuntu.sh

@@ -27,7 +27,7 @@ apt-get -y install zlib1g-dev
 # optional for gnunet-conversation
 # apt-get -y install libpulse-dev libopus-dev libogg-dev gstreamer1.0
 # optional for gnunet-qr
-apt-get -y install python-zbar
+apt-get -y install libzbar-dev
 # optional for experimental code
 apt-get -y install libglpk-dev
 #

doc/system_specific/FROM_SOURCE

@@ -534,7 +534,7 @@ at all.
 We begin by installing a few Debian packages from stable:@
 
 @example
-# apt-get install gcc make python-zbar libltdl-dev libsqlite3-dev \
+# apt-get install gcc make libzbar-dev libltdl-dev libsqlite3-dev \
   libunistring-dev libopus-dev libpulse-dev openssl libglpk-dev \
   texlive libidn11-dev libmysqlclient-dev libpq-dev libarchive-dev \
   libbz2-dev libexiv2-dev libflac-dev libgif-dev libglib2.0-dev \
@@ -778,7 +778,7 @@ as a normal user.
 We begin by installing a few Debian packages from stable:
 
 @example
-# apt-get install gcc make python-zbar libltdl-dev libsqlite3-dev \
+# apt-get install gcc make libzbar-dev libltdl-dev libsqlite3-dev \
 libunistring-dev libopus-dev libpulse-dev openssl libglpk-dev texlive \
 libidn11-dev libmysqlclient-dev libpq-dev libarchive-dev libbz2-dev \
 libflac-dev libgif-dev libglib2.0-dev libgtk-3-dev libmpeg2-4-dev \