$expr and the first aggregation stages ### Kotlin BSON - Fixed bug where arrays were generated incorrectly (9d0cbea3, !20) ### MongoDB DSL - Create the aggregation Value (bec086c1) - Create the $expr filter operator (22b9d97e) - Add the $match aggregation stage (44ea7bf3) - Add the $sample aggregation stage (fc34f2b5) - Add the $skip aggregation stage (3239a479) - Add the $limit aggregation stage (4cc84722) - Add the $set aggregation stage (81b7f8b4) - Implement the $literal aggregation operator (49e1d564) - Implement the $eq, $ne, $gt, $lt, $gte, $lte aggregation operators (22b9d97e)