vectorize []-method
add dim support in obj[]
add data.table dependency
change method for reading data.table
Update cdb-class.r

possible fix to #23
Merge branch 'master' into issue-11-read-all

* master:
  Update README.md
  add yaml support
  add yaml dependency
  Update tests
  Add forze_tz to POSIX conversion
  Add lubridate dependency
  Update readme
  Remove timezone attributes => only GMT
  Add tests
=> v0.4
change type default: "n" -> "f"
update dependencies
Merge pull request #23 from SthlmR/issue-11-read-all

vectorize []-method