Documentation fixes: Updated the contents of README.plib and README.OpenAL

Also make sure that these files are included in the release. This is
required, since ./configure refers to these files.

Makefile.am

@@ -4,6 +4,8 @@ EXTRA_DIST = \
 	DoxygenMain.cxx \
 	README.MSVC \
 	README.zlib \
+	README.plib \
+	README.OpenAL \
 	projects \
 	SimGear.dsp \
 	SimGear.dsw

README.OpenAL

@@ -7,6 +7,25 @@ to build FlightGear!"  You can get a copy here:
 
 Build notes:
 
-The OpenAL developers do not make "versioned" releases so we recommend that
-you pull the latest version via anonymous CVS (follow the instructions at
+You can download a versioned release of the openal library from 
+http://www.openal.org/downloads.html. Download the openal source,
+release 0.0.8 (dated February 11, 2006) and run:  
+tar xzvf openal-0.0.8.tar.gz
+cd openal-0.0.8
+./autogen.sh
+./configure
+make
+sudo make install
+
+The alut library is also required, but comes separately in the package
+freelut-1.1.0.tar.gz. This package can be downloaded from the same page
+(http://www.openal.org/downloads.html). Download and run:
+tar xzvf freelut-1.1.0.tar.gz
+cd freelut-1.1.0
+./autogen.sh
+./configure
+make
+sudo make install
+
+Alternatively, you can use the CVS version (follow the instructions at
 the OpenAL web site) and build/install that.

README.plib

@@ -1,6 +1,6 @@
 [This file is mirrored in both the FlightGear and SimGear packages.]
 
-You *must* have plib version 1.6.0 or later installed on your system
+You *must* have plib version 1.8.4 or later installed on your system
 to build FlightGear!"  Flight Gear is no longer compatible with the
 earlier versions of the library.