rm: Use real backtick and tick. Closes #28.

* src/dctc/java/com/dataiku/dctc/command/Rm.java: Here.
move: GoogleFile -> GSFile.

* src/dctc/java/com/dataiku/dctc/file/GoogleFile.java: Move to...
* src/dctc/java/com/dataiku/dctc/file/GSFile.java: ...Here.

* src/dctc/java/com/dataiku/dctc/command/AddAccount.java,
  src/dctc/java/com/dataiku/dctc/file/GSFileBuilder.java: Adjust.
gs: list the entire bucket. Closes #29.

* src/dctc/java/com/dataiku/dctc/file/GSFile.java: The list was
  chuncked. Iterate on it to get whole files.