Re-organize and improve help command and help info for each command

libexec/tmuxifier-load-session

@@ -2,6 +2,17 @@
 set -e
 [ -n "$TMUXIFIER_DEBUG" ] && set -x
 
+# Provide tmuxifier help
+if [ "$1" == "--help" ]; then
+  echo "usage: tmuxifier load-session <layout_name>
+
+Aliases: session, ses, s
+
+Create a session using the session layout, unless the session already exists
+in which case, we simply attach/switch to the existing one."
+  exit
+fi
+
 # Provide tmuxifier completions
 if [ "$1" == "--complete" ]; then
   for item in $(tmuxifier-list-sessions); do