v0.1.0

• implement binary operators (+, -, *, /, %, ==, !=, >, <, >=, <=, and, or)
• implement unary operators (+, -)
• implement booleans (false, true), null, number and string constant values
• implement empty value
• implement conditional syntax (if then elif else end)
• implement builtin functions (length, utf8bytelength, not, keys, has, map, select, recurse, while, until, range, tonumber, type, arrays, objects, iterables, booleans, numbers, strings, nulls, values, scalars, reverse, explode, implode, join)
• support function declaration
• support iterators in object keys
• support object construction shortcut
• support query in array indices
• support negative number indexing against arrays
• support json file name arguments