Changed pico to nano as default editor

doc/index.html

@@ -66,7 +66,7 @@ entire image is created, and will <b><i>overwrite</i></b> any
 and image to be edited in a text-based xml-style format (like the
 output of <kbd>fslhd -x</kbd> but with redundant fields removed
 and some help text provided).  Note that
-the default text editor used is pico, but other editors can be
+the default text editor used is nano, but other editors can be
 specified by the second argument.
 
 <br><br><LI><b>fslfft</b> - outputs the Fast-Fourier Transform (or inverse)

fsledithd

@@ -24,7 +24,7 @@ if [ _$FSLDIR = _ ] ; then
 fi
 
 if [ X$FSLEDITOR = X ] ; then
-    FSLEDITOR=pico
+    FSLEDITOR=nano
 fi
 if [ $# -ge 2 ] ; then
     FSLEDITOR=$2