calc/calc.el (calc-simplify-mode): Make 'alg the default value.

calc/calc.el (calc-simplify-mode): Make 'alg the default value.
(calc-set-mode-line): Don't display "AlgSimp ".

calc/calc-mode.el (calc-alg-simplify-mode): Remove function.
(calc-lim-simplify-mode): New function.
(calc-set-simplify-mode): Default to 'alg.
(calc-default-simplify-mode): Make algebraic simplifications the default.

calc/calc-ext.el (calc-init-extensions): Remove binding for
`calc-alg-simplify-mode'. Add binding for `calc-lim-simplify-mode'.

calc/README: Mention new default simplification mode.