add fakefs for testing
add fakefs spec and dependency
reads from standard input
3 tests for: 1. write memos to a file 2. create file extension 3. create filename
store function: write input to file file_name function: generates file name
Merge branch 'master' into review_140903_infra

* master:
  add rake to Gemfile
  add whitespace

Conflicts:
	Gemfile
	Gemfile.lock
Merge pull request #5 from NadjaW/review_140903_infra

Review 140903 infra