message: upgrade the file to use the correct package name and include py3/gtk3 support
diff: @@ -5,7 +5,7 @@ Goals
  -----
  In this tutorial We will learn to setup OpenCV-Python in Ubuntu System.
  -Below steps are tested for Ubuntu 16.04 (64-bit) and Ubuntu 14.04 (32-bit).
  +Below steps are tested for Ubuntu 16.04 and 18.04 (both 64-bit).
  OpenCV-Python can be installed in Ubuntu in two ways:
  - Install from pre-built binaries available in Ubuntu repositories
  @@ -62,18 +62,36 @@ We need **CMake** to configure the installation, **GCC** for compilation, **Pyth
  ```
  sudo apt-get install cmake
  -sudo apt-get install python-dev python-numpy
  sudo apt-get install gcc g++
  ```
  +to support python2:
  +
  +```
  +sudo apt-get install python-dev python-numpy
  +```
  +
  +to support python3:
  +
  +```
  +sudo apt-get install python3-dev python3-numpy
  +```
  -Next we need **GTK** support for GUI features, Camera support (libv4l), Media Support
  +Next we need **GTK** support for GUI features, Camera support (v4l), Media Support
  (ffmpeg, gstreamer) etc.
  ```
  -sudo apt-get install gtk2-devel
  -sudo apt-get install libv4l-devel
  -sudo apt-get install ffmpeg-devel
  -sudo apt-get install gstreamer-plugins-base-devel
  +sudo apt-get install libavcodec-dev libavformat-dev libswscale-dev
  +sudo apt-get install libgstreamer-plugins-base1.0-dev libgstreamer1.0-dev
  +```
  +
  +to support gtk2:
  +```
  +sudo apt-get install libgtk2.0-dev
  +```
  +
  +to support gtk3:
  +```
  +sudo apt-get install libgtk-3-dev
  ```
  ### Optional Dependencies
  @@ -87,14 +105,15 @@ But it may be a little old.
  If you want to get latest libraries, you can install development files for system libraries of these formats.
  ```
  -sudo apt-get install libpng-devel
  -sudo apt-get install libjpeg-turbo-devel
  -sudo apt-get install jasper-devel
  -sudo apt-get install openexr-devel
  -sudo apt-get install libtiff-devel
  -sudo apt-get install libwebp-devel
  +sudo apt-get install libpng-dev
  +sudo apt-get install libjpeg-dev
  +sudo apt-get install libopenexr-dev
  +sudo apt-get install libtiff-dev
  +sudo apt-get install libwebp-dev
  ```
  +@note If you are using Ubuntu 16.04 you can also install ```libjasper-dev``` to add a system level support for the JPEG2000 format.
  +
  ### Downloading OpenCV
  To download the latest source from OpenCV's [GitHub Repository](https://github.com/opencv/opencv).
  