Using printing and parsing library from QuickJS.

Using printing and parsing library from QuickJS.

- Number.prototype.toString(radix)
    Improved accuracy for edge cases
    Reimplemented using njs_dtoa2() with JS_DTOA_FORMAT_FREE | JS_DTOA_EXP_DISABLED
- Number.prototype.toFixed(frac)
    Reimplemented using njs_dtoa2() with JS_DTOA_FORMAT_FIXED
    Removed old njs_fixed_dtoa() implementation
- Number.prototype.toPrecision(prec)
    Reimplemented using njs_dtoa2() with precision format
    Removed old njs_dtoa_precision() implementation
- Number.prototype.toExponential(frac)
    Reimplemented using njs_dtoa2() with exponential format
    Removed old njs_dtoa_exponential() implementation
- parseInt()
    Simplified parsing implementation
    Removed custom njs_number_radix_parse() helper
- parseFloat()
    Simplified parsing implementation

Removed custom njs_number_bin_parse(), njs_number_oct_parse(),
njs_number_dec_parse() and njs_strtod.c module Better handling of large
numbers and denormal floats and invalid inputs.