v2.0.0

• Full reentrancy, supporting multiple concurrent evaluations of the same Expression object
• New multithreading model independent of Node.js/libuv
• Support OpenMP-style parallelism in map/mapAsync and cwise/cwiseAsync
• Support writing into a preallocated array for Expression.prototype.map
• Support passing TypedArray subarrays (TypedArray.prototype.subarray)
• Expression.prototype.toString()
• Add a shared superclass Expression supporting testing with instanceof
• Expression.prototype.allocator() allowing to call the TypedArray constructor