FLUME-2105. Add docs for MorphlineSolrSink.

(Wolfgang Hoschek via Mike Percy)
FLUME-2106. Update 1.4.0-SNAPSHOT to 1.5.0-SNAPSHOT on trunk.

(Mike Percy)
FLUME-2108. Update RELEASE-NOTES and CHANGELOG for 1.4.0 release.

(Mike Percy)
FLUME-2108. Corrections to CHANGELOG for 1.4.0 release.

(Mike Percy)