add function to dataset to retrieve the remote columns on GD
add functions to schema.utils to read information from remote columns on GD
initialize a test to check the get_remote_columns function
implement retrieve_dlc_info, that retrieve data information on columns (datatype, references)
add dataset.get_remote_sli_manifest, useful for datetimes and references
add dlc_info support to retrieve columns: some columns cannot be rebuilt from a sole entrypoint....
in dataset.get_remote_column, call get_remote_sli_manifest and retrieve_dlc_info
modify some examples to make them more complete and add a test to test get_remote_columns
split dataset between Dataset and State classes
add new exceptions
add using querying in Project
bugfix on shema.utils + get_references
modify the tests and make them work \O/
Merge branch 'master' into mvdb/501/retrieve-GD-columns-objects

Conflicts:
	gooddataclient/exceptions.py
removed unused imports in dataset.py
fix a bug on migrations for Label/Hyperlink changes
fix import errors in test_state and state module
Merge pull request #17 from Work4Labs/mvdb/501/retrieve-GD-columns-objects

Mvdb/501/retrieve gd columns objects