Implement map/map fusion of program-fusion

[hisaway]

Is your feature request related to a problem? Please describe.

Written codes with pipe is so readable, however it is not efficient because exist temporary datas between pipes.

Describe the solution you'd like

When optimizer found succession of pipes and Enum.map, merge computation which be send as argument into one liner.

Describe alternatives you've considered

Use GHC and NIF, after we make GHC parser for a part of Elixir.

Additional context

Elixir is not pure functional programming language, so I think that verifying strictly code transformation is difficult.

[zacky1972]

I request you to make a lot of effort to solve this issue, more than any other issues, @hisaway Other issues is less important for me than this issue.