Merge branch 'replicaset-support' of https://github.com/benoitlouy/RMongo into replicaset-support

# By Tommy Chheng (30) and others
# Via Tommy Chheng (2) and others
* 'replicaset-support' of https://github.com/benoitlouy/RMongo: (41 commits)
  Add support for connection to Mongo DB replica sets. Add support for Mongo write concern.
  updated to support R 3.0; updated mongo-java-driver to 2.11.2
  update version to 0.0.23 for aggregration framework support
  removed quote wrappings in return value of dbAggregate and make it return an array of strings rather than a single string.
  removed quote wrappings in return value of dbAggregate and make it return a vector rather than string.
  clean tests and output with aggregation support
  clean build of jar file with aggregate support
  these are not working currently, error on examples
  Failing to get connection between R and Scala
  Upgrading mongo drivers and aggregation test
  First attempt to support the "aggregate" function within mongo.
  corrected changelog credits
  corrected credit in readme
  fix docs
  added comments for new methods
  readme notes for publishing to cran
  updated notes for 0.0.22
  Fixed a bug in toCsvOutput which caused R data frames to be restricted to the fields of the first record found by a query.
  corrected project url
  Added methods for removing data from collections and to list all unique values.
  ...
Merge pull request #20 from benoitlouy/replicaset-support

Add support for ReplicaSet connection and WriteConcern
Merge pull request #21 from benoitlouy/2.14.1-compatibility

2.14.1 compatibility
updated to 0.0.25 release