Created Tag and Commit Merge functions and Created Indexes for the crawler

-- Replaced Parent with Parents (Tag and Commit field) in the codes that use them.
-- Created type parents as a slice of HCID and for loop to turn parents into a string.
-- Created a for loop in the crawler to loop through the parents fields in the commits and tags in the crawler incase of multiple parents instances.
-- Created four variables (tagIndex, commitIndex, listIndex and blobIndex) to handle indexing of the blobs, lists, commits and tags.
-- Created the indexBlob, indexList, indexCommit and indexTag functions to handle indexing of blobs and lists.
Merge branch 'master' of github.com:AaronGoldman/ccfs
Merge branch 'master' of github.com:AaronGoldman/ccfs