saugns v0.3.11b. Further syntax tweaks. Small fixes.

Syntax changes:
 * For modulation with value range, change delimiters
   between the parts from "Xw,Y[...]" to "X,wY[...]".
 * For frequency-amplified PM, ',' added before 'f['.
 * Allow numerical expressions to omit "*" after ")",
   not only before "(", for shorthand multiplication.

There is no longer any need to sometimes place named
constants in parentheses to separate them from added
"w" or "f" after, as "," is now placed between them.

Reduce rounding error for numbers read from scripts.
Precision improved from a little better than single,
to just below double. Practically, the difference is
small, since output from the parser is still reduced
to single precision after the numerical expressions.
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