ref-manual: Scrubbed for variable (user) input.

Throughout the manual I had been using angled bracket sets to
denote user-supplied input.  This is confusing and better shown
by using the <replaceable></replaceable> tags.  I scrubbed all
the chapters and replaced as needed.

Some other minor formatting changes were caught and fixed during
the scrub as well.

(From yocto-docs rev: 9a668574dd18828a750cfa2e8c28e1f089a19609)

Signed-off-by: Scott Rifenbark <scott.m.rifenbark@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

documentation/ref-manual/ref-structure.xml

@@ -315,7 +315,7 @@
             commands.
             Following is the script syntax:
             <literallayout class='monospaced'>
-     $ source oe-init-build-env-memres &lt;port_number&gt; &lt;build_dir&gt;
+     $ source oe-init-build-env-memres <replaceable>port_number</replaceable> <replaceable>build_dir</replaceable>
             </literallayout>
             The script uses other scripts within the
             <filename>scripts</filename> directory to do the bulk of the work.
@@ -499,7 +499,7 @@
             the variable in the top-level build environment setup script as
             follows:
             <literallayout class='monospaced'>
-     TEMPLATECONF=&lt;your_layer&gt;/conf
+     TEMPLATECONF=<replaceable>your_layer</replaceable>/conf
             </literallayout>
             Once the build process gets the sample file, it uses
             <filename>sed</filename> to substitute final
@@ -554,7 +554,7 @@
             you can base your build from any layer by setting the variable in
             the top-level build environment setup script as follows:
             <literallayout class='monospaced'>
-     TEMPLATECONF=&lt;your_layer&gt;/conf
+     TEMPLATECONF=<replaceable>your_layer</replaceable>/conf
             </literallayout>
             Once the build process gets the sample file, it uses
             <filename>sed</filename> to substitute final