[doc] High level overview.

[David Farning <dfarning@gmail.com>]

I am adding three high-level overview sections to getting started.
Each of these list items will be expanded into a paragraph introducing
the concept and how BB/OE solves the problem.

The first section describes what a development system must be able to do.
The second section describes what a OE developer must be able to define.
The third section describes the Outputs of bb/oe.

The section listed concepts are intentionally redundant because they
will look at the concepts from the three point of view:  What does the
system do, how do we tell the system what to do, what the system
outputs.

Please take a look and let me know if I am missing any big concepts.

thanks
David Farning

1
*************************
      <para>Before we get into the details of installing
<application>BitBake</application> let's step back and look at
      our goals.  As embedded developers we want to create a
specialized Linux <glossterm>distribution</glossterm>
      that will run on our <glossterm>device</glossterm>.
      This requires a number of things from our build system.

      <itemizedlist>
        <listitem>
          <para>Download Source Files - Grab source files, on the fly,
from upstream projects rather than
          from a central repository</para>
        </listitem>
        <listitem>
          <para>Apply Patches - Apply patches to source files which
will enable the compiled binaries
          to run on non-standard devices.</para>
        </listitem>
        <listitem>
          <para>Configure Applications</para>
        </listitem>
        <listitem>
           <para>Cross Compile - Compile executables that will run on
the target device.</para>
        </listitem>
        <listitem>
          <para>Create Packages</para>
        </listitem>
        <listitem>
          <para>Create File System - Create a root filesystem that
contains the installed packages.</para>
        </listitem>
        <listitem>
          <para>Build Image - Build an image that contains the file
system.</para>
        </listitem>
      </itemizedlist>
      </para>
****************

2
***************************
    <para>It is time to step back and look at our goals again.  In
order to create a linux distribution for an embedd device, we
    need to define.

      <itemizedlist>
        <listitem>
           <para>Define Applications</para>
        </listitem>
        <listitem>
          <para>Define Libaries.</para>
        </listitem>
        <listitem>
          <para>Define Kernel</para>
        </listitem>
        <listitem>
          <para>Define Archicture</para>
        </listitem>
        <listitem>
          <para>Define Package System</para>
        </listitem>
        <listitem>
          <para>Define File System</para>
        </listitem>
      </itemizedlist>
      </para>
************************

3
************************
    <para>It is time to step back and look at our goals again.  We
want to create an image which we can deploy.
    This impiles

      <itemizedlist>
        <listitem>
          <para>Create Cross Compiler.</para>
        </listitem>
        <listitem>
          <para>Create installable Packages.</para>
        </listitem>
        <listitem>
           <para>Create a deployable image.</para>
        </listitem>
      </itemizedlist>
      </para>
*************************