Updates to Dockerfile to fix compatibility issues

[SwapnilGaikwad]

• Update docker file CMD to be compatible with docker version 18.03 format and avoid the following errror. docker: Error response from daemon: OCI runtime create failed: container_linux.go:348: starting container process caused "exec: \"mx R\": executable file not found in $PATH": unknown.

• The FastR implementation uses R 3.4.0.

• Export LANG to use UTF-8 to avoid the following warnings when R is started.

  > $ docker run --rm -it fastr
  > R version 3.4.0 (FastR)
  > Copyright (c) 2013-18, Oracle and/or its affiliates
  > Copyright (c) 1995-2017, The R Core Team
  > Copyright (c) 2017 The R Foundation for Statistical Computing
  > Copyright (c) 2012-4 Purdue University
  > Copyright (c) 1997-2002, Makoto Matsumoto and Takuji Nishimura
  > All rights reserved.
  > 
  > FastR is free software and comes with ABSOLUTELY NO WARRANTY.
  > You are welcome to redistribute it under certain conditions.
  > Type 'license()' or 'licence()' for distribution details.
  > 
  > R is a collaborative project with many contributors.
  > Type 'contributors()' for more information.
  > 
  > Type 'q()' to quit R.
  > Setting LC_COLLATE failed, using default
  > Setting LC_MONETARY failed, using default
  > Setting LC_TIME failed, using default
  > Setting LC_MESSAGES failed, using default
  > 

[nuest]

Thanks for the fix!

By submitting this PR you agree that your contribution is licensed under the terms defined in LICENSE and REAMDE.md - let me know if you have any problems with that asap!

Can you tell me what you're dowing with fastr respectively this docker image?

[SwapnilGaikwad]

Hello @nuest, thanks for merging a pull request. I have no issues with the LICENCE and README.md.

I had submitted another issue related to Perl compatible regular expression support in fastR while running the regular expression-based benchmark. and bumped on to the issue that you submitted. I just gave this image a spin out of curiosity. Can we close the fastR issue in this case?

Thanks, Swapnil