acu81679 - add support for map<text, text> collection type
acu81679 - add support to handle map<text, text> binding in the stmt prepare&exec.
acu81679 - wording correction + clearer expression
Merge pull request #1 from rightscale/blue_13_03_acu81679_attrs_and_metrics_table

acu81679 - add support for map<text, text> collection type