Fix shebang of a few bash scripts

doc/examples/anim09/anim09.sh

@@ -19,7 +19,7 @@
 # The movie took ~6 hours to render on a 24-core MacPro 2013.
 
 cat << EOF > pre.sh
-#!/bin/bash
+#!/usr/bin/env bash
 # Pre-script: Runs once to produce files needed for all frames
 gmt begin
 	gmt grdgradient @earth_relief_30s -A90 -Nt2.5 -Gearth_relief_30s+2.5_int.nc
@@ -34,7 +34,7 @@ WIDTH=36
 HEIGHT=34
 EOF
 cat << EOF > main.sh
-#!/bin/bash
+#!/usr/bin/env bash
 # Main frame script that makes a single frame given the location and twist from the data file
 # and the other view parameters from the include file.
 gmt begin

doc/scripts/GMT_fatline.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 # This script demonstrates the problem with the basic line rendering
 # algorithm in ghostscript for fat lines.
 # https://github.com/GenericMappingTools/gmt/issues/431

doc/scripts/GMT_seamount_flux.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 # Illustrate the two different volume-flux curves
 ps=GMT_seamount_flux.ps
 gmt set FONT_ANNOT_PRIMARY 14p

doc/scripts/GMT_seamount_map.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 # Illustrate the circular and elliptical bases of seamounts
 ps=GMT_seamount_map.ps
 gmt set MAP_VECTOR_SHAPE 0.5

doc/scripts/GMT_seamount_types.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 # Plot four different seamount types selectable in grdseamount
 # 1. Conical seamount
 gmt set MAP_VECTOR_SHAPE 0.5
@@ -141,4 +141,4 @@ gmt pstext -R -J -O -K -F+f16p,Times-Italic+j -N << EOF >> $ps
 EOF
 echo "@%1%d@%% (disc)" | gmt pstext -R -J -O -F+f18p+cTL -Dj0.1i >> $ps
 
-rm -f tmp body line
+rm -f tmp body line

test/pslegend/autolegend.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 gmt begin autolegend ps
   gmt plot -R0/7.2/3/7.2 -Jx1i -B @Table_5_11.txt -Sc0.15i -Glightgreen -Wfaint -lApples+H"LEGEND"+f16p+D
   gmt plot @Table_5_11.txt -W1.5p,gray -l"My Lines"

test/pssac/pssac_stdin.sh

@@ -1,4 +1,4 @@
-#!bin/bash
+#!/usr/bin/env bash
 #
 # Description: