v0.3.0

• implement reduce, foreach, label, break syntax
• improve binding variable syntax to bind to an object or an array
• implement string interpolation
• implement object index by string (."example")
• implement various functions (add, flatten, min, min_by, max,
  max_by, sort, sort_by, group_by, unique, unique_by, tostring,
  indices, index, rindex, walk, transpose, first, last, nth,
  limit, all, any, isempty, error, builtins, env)
• implement math functions (sin, cos, tan, asin, acos, atan,
  sinh, cosh, tanh, asinh, acosh, atanh, floor, round,
  rint, ceil, trunc, fabs, sqrt, cbrt, exp, exp10, exp2,
  expm1, frexp, modf, log, log10, log1p, log2, logb,
  gamma, tgamma, lgamma, erf, erfc, j0, j1, y0, y1,
  atan2/2, copysign/2, drem/2, fdim/2, fmax/2, fmin/2, fmod/2,
  hypot/2, jn/2, ldexp/2, nextafter/2, nexttoward/2, remainder/2,
  scalb/2, scalbln/2, pow/2, yn/2, fma/3)
• support object construction with variables
• support indexing against strings
• fix function evaluation for recursive call
• fix error handling of // operator
• fix string representation of NaN and Inf
• implement -R flag for reading input as raw strings
• implement -c flag for compact output
• implement -n flag for using null as input value
• implement -r flag for outputting raw string
• implement -s flag for reading all inputs into an array