Darwin updates

Add Python modules that are needed for work and other things
Move import of Bash into Xonsh to the head in order to avoid issues with
being overwritten by Bash defaults

home/xonsh.nix

@@ -47,6 +47,9 @@
 		};
 
 		configHeader = ''
+if  '__NIX_DARWIN_SET_ENVIRONMENT_DONE' not in ''${...} or not $__NIX_DARWIN_SET_ENVIRONMENT_DONE:
+    source-bash /etc/bashrc
+
 # set -e == $RAISE_SUBPROC_ERROR = True
 # set -x == trace on; $XONSH_TRACE_SUBPROC = True
 # $? == _.rtn
@@ -126,9 +129,6 @@ import builtins
 builtins.true = True
 builtins.false = False
 builtins.null = None
-
-if  '__NIX_DARWIN_SET_ENVIRONMENT_DONE' not in ''${...} or not $__NIX_DARWIN_SET_ENVIRONMENT_DONE:
-    source-bash /etc/bashrc
 '';
 	};
 }