calc-aent.el (math-read-token, math-find-user-tokens):

calc-aent.el (math-read-token, math-find-user-tokens):
calc-lang.el (math-read-big-rec, math-lang-read-symbol)
(math-compose-tex-func):
calccomp.el (math-compose-expr):
calc-ext.el (math-format-flat-expr-fancy):
calc-store.el (calc-read-var-name):
calc-units.el (calc-explain-units-rec): Allow Greek letters.

calc.el (var-π, var-φ, var-γ): New variables.

calc-aent.el (math-read-replacement-list):  Add "micro" symbol.

calc-units.el (math-unit-prefixes): Add mu for micro.
(math-standard-units):  Add units.