Adding greeting screen and dependency tree.

Signed-off-by: Damian Rouson <[email protected]>

Author: Damian Rouson

doc/dependency_tree/opencoarrays-tree

@@ -0,0 +1,9 @@
+opencoarrays/
+├── cmake-3.4.0
+└── mpich-3.1.4
+    └── gcc-5.1
+        ├── flex-2.6.0
+        │   └── bison-yacc-3.0.4
+        ├── gmp
+        ├── mpc
+        └── mpfr

install.sh

@@ -108,8 +108,8 @@ usage()
     echo "      $this_script [<options>] or [<installation-path> <number-of-threads>]"
     echo ""
     echo " Options:"
-    echo "   -h, --help       Show this help message"
-    echo "   -v, --version    Show version information"
+    echo "   -h, --help          Show this help message"
+    echo "   -v, -V, --version   Show version information"
     echo ""
     echo " Examples:"
     echo ""
@@ -615,10 +615,45 @@ find_or_install()
   fi # End 'if [[ "$package" != "none" ]]; then'
 }
 
+print_header()
+{
+  clear
+  echo ""
+  echo "*** A default build of OpenCoarrays requires CMake 3.4.0 or later     ***"
+  echo "*** and MPICH 3.1.4 wrapping GCC Fortran (gfortran) 5.1.0 or later.   ***"
+  echo "*** Additionally, CMake, MPICH, and GCC have their own prerequisites. ***"
+  echo "*** This script will check for most known requirements in your PATH   ***"
+  echo "*** environment variable and in the default installation directory    ***"
+  echo "*** to which this script installs each missing prerequisite.  The     ***" 
+  echo "*** script will recursively traverse the following dependency tree    ***"
+  echo "*** and ask permission to download, build, and install any missing    ***"
+  echo "*** prerequisites:                                                    ***"
+  echo ""
+  tree $opencoarrays_src_dir/doc/dependency_tree | tail -n+2 
+  echo ""
+  echo "*** All prequisites will be downloaded to, built in, and installed in ***"
+  echo "$opencoarrays_src_dir/install_prerequisites"
+  printf "*** OpenCoarrays will be installed "
+  if [[ "$install_path" == "$opencoarrays_src_dir/opencoarrays-installation" ]]; then 
+    printf "in the above location also.        ***\n"
+  else
+    printf "in                                 ***\n"
+    echo "$install_path"
+  fi  
+
+  printf "Ready to proceed? (y/n)"
+  read install_now
+  if [[ "$install_now" != "y" ]]; then
+    printf "\n$this_script: Aborting. [exit 85]\n"
+    exit 85
+  fi
+}
+
+
+
 build_opencoarrays()
 {
-  # A default OpenCoarrays build requires CMake and MPICH. Secondary 
-  # dependencies will be found or installed along the way.
+  print_header
   find_or_install mpich    &&
   find_or_install cmake    &&
   mkdir -p $build_path     &&