* import rlang
* refactoring
* refactored and tests passing again
* add tests for kql-escape
* added arrange function
* remove purrr dependency
* merge namespace file
* start working on group_by, summarize, and ungroup
* finalize changes to replace AzureDataExplorer with AzureKusto name
* implemented group_by and summarise
* make mutate() work with agg functions
* add rename() verb
* add head() verb
* start implementing join
* add tbl_kusto class
* implement collect() verb
* make render() quote the database name for show_query and collect
* get basic one-column inner join working
* add basic support for one-column left, right, outer, anti, semi joins
* handle join on one differently-named column
* make join work with multiple differently named columns
* add verb: union_all as this is the only setop flavor supported by Kusto
* error on unsupported setops
* remove DBI stuff for now
* remove DBI as an import
* remove DBITest from suggested imports
* add rlang to imports list in DESCRIPTION
* various cleanup
* rename tbl_abstract to tbl_kusto_abstract
* remove call to as.tibble in collect()
* add tibble to Imports and call as.tibble in collect() method
* add tibble to Imports and call as.tibble in collect() method
* remove tibble from DESCRIPTION and call dplyr::as_tibble instead
Alex Kyllo