setup.py: fix google-api-python-client dependency
request: add support for DOUBLE and CURRENCY data types
request: add Request._create_record()

The function takes a record type and a dictionary of data and
returns an instance of the record type containing the
records data.
test: add CURRENCY metric
test: add a test for callable service attribute
gaclient: version bumped to 0.2 (was 0.0.1)