PNaCl: refactor unary operations
PNaCl: refactor unary operations

Added explanatory comments
Handle over-writing of existing array
Short-cut for in-place operation

amd/furious.js,faizanv/furious.js,beni55/furious.js,hpcgarage/furious.js,faizanv/furious.js,hpcgarage/furious.js,beni55/furious.js,faizanv/furious.js,beni55/furious.js,hpcgarage/furious.js,hpcgarage/furious.js,amd/furious.js,amd/furious.js,beni55/furious.js,amd/furious.js,faizanv/furious.js,amd/furious.js