Add some instructions to download and compile cvs openh323 and chan_h323

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@738 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/h323/INSTALL.openh323

+Here are some basic instructions how to download and compile the code from openh323.org CVS and how to install chan_h323. You must be logged as root.
+
+> cd /root (Notice that pwlib has it hardcoded to compile from /root)
+> export CVSROOT=:pserver:openh323@cvs.openh323.org:/home/cvsroot
+> cvs login (password is openh323)
+> cvs checkout openh323 pwlib ptlib_unix
+> cd pwlib; make all install
+> cd ../openh323; make all install
+> echo /usr/local/lib >> /etc/ld.so.conf
+> ldconfig
+> cd /usr/src/asterisk/channels/h323
+> make install
+> cp h323.sample.conf /etc/asterisk/h323.conf
+
+Now you have to edit the /etc/asterisk/h323.conf config file.
+