Expose JS path string -> path array function

[joshuacc]

@megawac @AlphaGit I think exposing the parsing function from #175 is a good idea. Suggestions on naming?

[AlphaGit]

Just to make it explicit: the function takes a JavaScript notation path and outputs an array with the list of accessors (properties?) to access in each level.

I like over-specific names but I think that's against the normal naming of the library, on which functions are usually called 1 or 2-word name functions.

That being said, how about the following?

• _.parseKeys
• _.parsePath (same input as getPath and hasPath, consistency is good too)
• _.getKeys
• _,keysFromPath

[megawac]

:+1: keysFromPath