Make get/put more robust

  - init folder if not present already in 'get()' call
  - put.go was referencing wrong args - fix it
  - if no OBJECTNAME is specified during 'get' - grab a
    list of files under "~/.minio"
  - Provide new API GetList() for ObjectStorage struct
Merge pull request #99 from harshavardhana/pr_out_make_get_put_more_robust
Add crc32c checksum support for erasure chunks

Now upon conditions

 - if checksum '.cksum' file is missing
 - or corrupted chunk (mismatching chunk)
 - or missing chunk entirely

Decoding works consistently
Merge pull request #100 from harshavardhana/pr_out_add_crc32c_checksum_support_for_erasure_chunks

Add crc32c checksum support for erasure chunks
Fixing build
Merge pull request #101 from fkautz/pr_out_fixing_build

Fixing build
Adding List(path) to object storage definition and accompanying definition to fs
Merge pull request #102 from fkautz/pr_out_adding_list_path_to_object_storage_definition_and_accompanying_definition_to_fs