Merge pull request #2 from vvenkatr/DMapBuilder_restructure_file

DMapBuilder new file structure.
Allows the block-wise loading of data.
Merge pull request #8 from vvenkatr/replace_constructor_with_builder

Merged changes from vvenkatr branch.
Merge pull request #3 from vvenkatr/DMapBuilder_update_adding_firstkey_info

DMapBuilder Update : Adding Info in Global Trailer
Preparing for new release
Merge branch 'master' of https://github.com/hoffart/dmap
Preparing for v0.1.0
Updating to SNAPSHOT
Merge pull request #10 from vvenkatr/updates

Updated README and small changes.