[DOC] Added R to the list of languages with "high-level API" support in the…

[enragedginger]

… main README.

[enragedginger]

I just added another commit which makes some spelling / grammar updates to the quick-start MD file.

[srowen]

sbt is lower-case. jar seems equally upper and lower case, so, fine to change but on the whole I tend to leave things like that. I think the other changes are OK but not sure I'd bother with things that aren't obviously wrong, like an Oxford comma.

[enragedginger]

I've switched all usages of "SBT" back to "sbt". At one point in time, SBT stood for "Simple Build Tool," but I can't find any remaining evidence of that on their site, so I'm guessing they've moved away from that.

[srowen]

Although this is probably OK without a JIRA, that's exceptional. Please read https://cwiki.apache.org/confluence/display/SPARK/Contributing+to+Spark first. In particular this isn't tagged as [DOCS] for example. Minor stuff but I don't want to let people to skip this.

[srowen]

Fair enough about R. This LGTM. I would have put spaces around this dash but it's too small to bother with.

[SparkQA]

Test build #1727 has finished for PR 8646 at commit a2c5fce.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds the following public classes (experimental):
  • case class BlockFetchException(messages: String, throwable: Throwable)
  • class DCT(JavaTransformer, HasInputCol, HasOutputCol):
  • class SQLTransformer(JavaTransformer):
  • class StopWordsRemover(JavaTransformer, HasInputCol, HasOutputCol):
  • case class LimitNode(limit: Int, child: LocalNode) extends UnaryLocalNode
  • case class UnionNode(children: Seq[LocalNode]) extends LocalNode