= io: fix Tcp.SO.reuseAddress not being applied for outgoing connections, fixes #712

Backport of akka/akka@6ebf6717c9db4c57d5b918342f578a6120e19b5a

See https://github.com/akka/akka/pull/1849
! routing: rename implicit ChunkSizeMagnet constructor and parameters
! routing: rename LoggingParameter constructor parameters for documentation
! routing: `compressResponseIfRequested` used wrong magnet
= routing: reorder method definitions in EncodingDirectives
! routing: make `dynamicIf` a static (= not inner) class

For common usages, API should stay the same.
= build: remove debug println from build
= docs: add links to directives only in spray-routing documentation
= docs: exclude code like `entity = ` from being linked as a directive
= docs: document anyParams directive
= docs: BasicDirectives documentation
= docs: CachingDirectives documentation
= docs: CookieDirectives documentation
= docs: include `implicit` marker in signatures
= docs: ChunkingDirectives documentation
= docs: also highlight directives inside backticked inline code spans
= docs: DebuggingDirectives documentation
= docs: reworked FutureDirectives
= docs: EncodingDirectives documentation
= docs: ExecutionDirectives documentation