minor documentation cleanup
netty-1597: Rewrite ByteBufInputStream.readLine() to avoid IndexOutOfBoundsException and to behave more correctly for lines ending in '\r'.
Fix checkstyle
netty-1616: Adding a 'last' check to SpdyHttpEncoder.
[#1619] Fix bug in ChannelOutboundBuffer which could lead to invalid write order when fireChannelWritabilityChanged() write another message
Make PendingWrites recyclable to reduce GC pressure
[#1626] Use static fields for default values
[#1628] Fix bug in ReadOnlyByteByteBufferBuf where get operations threw ReadOnlyBufferException
Fix up ChannelPipeline javadocs by add lost "don't "
[#1630] Fix re-entrance bug in ChannelOutboundBuffer.remove(...)
[#1624] Fix resource leak when writing to a closed / not-open channel
[#1606] Reduce overhead during writes because of ChannelPromise validation
Fix types in javadocs
[#1612] Allow to disable resource leak detection via API
Remove ResourceLeakDetector.ENABLED / Replace ResourceLeakDetector.is/setDisabled() with is/setEnabled()

- Related: #1612
Remove an unnecessary empty line
[#1637] Check for null parameters
Fix compile error
Simplify the validation logic proposed in 25f96b164498988439c38baf6ff4c57763464824
Change the contract of ResourceLeakDetector.open() so that unsampled resources are recycled

- This also fixes the problem introduced while trying to implement #1612 (Allow to disable resource leak detection).