feat: storage block id prefixed with blockid(sha1)

The storage block id is now prefixed with the actual sha1 of the
blockdata. i.e block id

Some of the benefits:

1.We no longer need to query metadata to find the block id for the
corresponding storage id.
2. A performance boost for validation and cleanup service
3. Easy identification of oprhaned blocks if there is more than one
block that begins with the same sha1 in storage.
fix: separator must be '&' or ';'

- pep8 fix
- rename a test correctly
fix: simplify checking of separators
bugfix: os.listdir() is not sorted

explicitly sort, before applying marker or limit logic
fix: limits on limit query string

the max limit is now set to 1000, but if it aint specified its set to
80.

When a limit is greater than 80 but less than 1000, it is
allowed.

But any limit greater than 1000, is reset to 1000.
fix: remove +1 on default limit while determining limit
Merge remote-tracking branch 'upstream/master' into prefixsha1_storageid

Conflicts:
	deuce/drivers/blockstoragedriver.py
Enhancement: Make File ID easier to get

- Provide a header field for the file id when creating a file
- Client should not have to parse a URL to get the File ID
Bug Fix

- Don't re-use the variable
Merge pull request #202 from BenjamenMeyer/enhancement_easy_find_fileid

Enhancement: Make File ID easier to get
Merge pull request #198 from TheSriram/limit_fix

fix: limits on limit query string
Merge pull request #195 from TheSriram/prefixsha1_storageid

feat: storage block id prefixed with blockid(sha1)