Replace usage of StringBuilder by AppendableCharSequence for performance reasons
[#2033] Correctly handle adding of IdleStateHandler after Channel was already active and registered
Better buffer leak reporting

- Remove the reference to ResourceLeak from the buffer implementations
  and use wrappers instead:
  - SimpleLeakAwareByteBuf and AdvancedLeakAwareByteBuf
  - It is now allocator's responsibility to create a leak-aware buffer.
  - Added AbstractByteBufAllocator.toLeakAwareBuffer() for easier
    implementation
- Add WrappedByteBuf to reduce duplication between *LeakAwareByteBuf and
  UnreleasableByteBuf
- Raise the level of leak reports to ERROR - because it will break the
  app eventually
- Replace enabled/disabled property with the leak detection level
  - Only print stack trace when level is ADVANCED or above to avoid user
    confusion
- Add the 'leak' build profile, which enables highly detailed leak
  reporting during the build
- Remove ResourceLeakException which is unsed anymore
Allow specifying a custom charset for a multipart Attribute

- Fixed #2025
- Adapted from @BabyDuncan's pull request: #2031
- Overall ugliness clean-up
codec-memcache: increase default buffer size and only encode extras if set.
[#2041] Make PlatformDependent.isRoot0() work on solaris
Hide protocol detail from users
readableBytes() ==0 -> !isReadable()
Also record retain() and release()
Checkstyle
Add ReferenceCountUtil.releaseLater() to make writing tests easy with ReferenceCounteds
Fix false-positive leaks

- All derived buffers and swapped buffers of a leak-aware buffer must be wrapped again with the leak-aware buffer
Add missing synchronization
Fix NoSuchElementException raised by ChannelInitializer
Fix all leaks reported during tests

- One notable leak is from WebSocketFrameAggregator
- All other leaks are from tests
Revert "Fix NoSuchElementException raised by ChannelInitializer"

This reverts commit 3c453f5dbaf8524d46c9fb3285d2ea7ae8bdb5b6.
Fix NoSuchElementException raised by ChannelInitializer

.. again.
Fix buffer leak in AbstractMemoryHttpData
Fix a buffer leak in BinaryMemcacheObjectAggregatorTest
Fix a buffer leak in BinaryMemcacheObjectAggregatorTest