Add new thread security level to properties
Add default implementation of canContinue()
Fix docs
Make TimeLimiter usable outside of the PiiHttpProtocol class
Fix deadlock with loopback connections

- Remote objects could lock up if a request was made from main thread and
  ended up being served by the main thread in the same process.
- Added a unique id for each remote object and a local registry map that
  holds all remote object instances on the server side.
- Client now uses the ID to detect if it actually talking to itself. If so,
  it writes the HTTP request to a memory buffer and calls the remote
  object's protocol implementation directly. The response is stored in a
  memory buffer as well.
Make atomic integers comparable (equal, not equal)
Add std::declval to non-C++11 builds
Add missing include
Implement generic variant comparison

- Qt doesn't support comparisons of user types in QVariant. Impemented a
  work-around that uses the serialization registry.
Improve PiiVariant interface

- Added operator== and operator!=
- Code for most primitive type handling is now generated using preprocessor
  loops.
- Added typeName(), toQVariant() and data()
Fix possible self-assignment problem
Reorder function definitions

- Required to make Pii::equals() to work with matrices in variants.
Add equals() for comparing variants
Fix spacing
Add unit tests for new functionality
Add type name to error message
Add operator==
Shorten type names

- Changed "unsigned x" types to "ux"
Reorder includes
Add overload detection for operator==