BREAKING CHANGE: changed the name of P-E SPH to pressure-entropy from hopkins

configure.ac

@@ -855,7 +855,7 @@ fi
 # Hydro scheme.
 AC_ARG_WITH([hydro],
    [AS_HELP_STRING([--with-hydro=<scheme>],
-      [Hydro dynamics to use @<:@gadget2, minimal, hopkins, pressure-energy, default, gizmo, shadowfax debug default: gadget2@:>@]
+      [Hydro dynamics to use @<:@gadget2, minimal, pressure-entropy, pressure-energy, default, gizmo, shadowfax debug default: gadget2@:>@]
    )],
    [with_hydro="$withval"],
    [with_hydro="gadget2"]
@@ -876,7 +876,7 @@ case "$with_hydro" in
    minimal)
       AC_DEFINE([MINIMAL_SPH], [1], [Minimal SPH])
    ;;
-   hopkins)
+   pressure-entropy)
       AC_DEFINE([HOPKINS_PE_SPH], [1], [Pressure-Entropy SPH])
    ;;
    pressure-energy)