re-arranged tuple unit test
Merge branch 'unstable' of github.com:Neverlord/libcppa into unstable
fixed `to_string` for process_info
print stack trace on error and warning messages
log error in `uniform_type_info::from`
added 'override' identifiers
added doxygen comments to cppa::opencl::program
use message headers instead of different enqueues

this patch removes the functions `sync_enqueue` and `chained_sync_enqueue`;
instead, `enqueue` takes a message header that denotes wheter the message
is synchronous or asynchronous (this patch also prepares libcppa for the
addition of message routing and priorities)
Merge branch 'unstable' of github.com:Neverlord/libcppa into unstable
Clang compatibility patch

this patch fixes some issues with some clang versions
added prioritizing mixin header
fixed bug in proxy registry
priority-aware actors

this patch adds a new spawn option for priority-aware actors
and refactors libcppa's message passing; this version has a known
issue with network distributed group messaging
fixed GCC error
fixed another GCC bug
fixed several issues related to message priorities

this patch fixes several bugs that are related to the recently added
support for priorities; it also refactors the remote actors unit test
and improves logging
refactored type name mapping

type names are now mapped using a static lookup table; all built-in types
information instances are now members of uniform_type_info_map to get rid
of as much heap allocations as possible
Provide two missing includes.