hadley/dplyr — pull request #521 by piersharding (2014-08-01 22:47:47+00:00)
Title: src-impaladb: ImpalaDB support

* includes modifications to support explict column scoping
required to support joins with ImpalaDB
* semi-joins are done through the explicit LEFT SEMI JOIN syntax
* loading tables requires HDFS support via rhdfs
* note: IMpapaDB does not support anti-joins
* Force USE dbname as hive2 driver does not honour URI
* Fix column alias
* column alias is not always calculated correctly as it comes
from a nested sub query
* fix db_list_tables to scope to DB
* ImpalaDB can't create temporary tables
* add option to documentation