Fixed #168: added constant `phi`, the golden ratio
Renamed function `unary` to `unaryminus`. Documented and tested constant `phi`.
Implemented unary plus
Removed array/matrix support from function `ifElse`
Implemented constant `version`, returnin the current version of math.js
Removed automatic assignment of expression results to variable `ans`
Moved functions `random`, `randomInt` and `pickRandom` to a separate file
Fixed random functions returning a Matrix on Array input
Fixed #65:  Fixed random functions not accepting Matrix as input, and always returning a Matrix as output
Added unit drop (gtt)
Renamed functions `edivide`, `emultiply`, and `epow` to `dotdivide`, `dotmultiply`, and `dotpow` respectively.
Added reference docs of renamed functions