Merge throws on previous line to appease both checkstyle 5.6 and 5.7

See pull request #1538 for discussion.
Merge pull request #1542 from scop/checkstyle2

Merge throws on previous line to appease both checkstyle 5.6 and 5.7
refactor client protocol
renaming Method CreateChannel to createSessionContext
new consumer close method
abstract session on consumer
abstract session on producer
initial session abstraction