consisten constructor calls
Merge branch 'unstable' of github.com:Neverlord/libcppa into unstable
Merge branch 'unstable' of github.com:Neverlord/libcppa into unstable
Merge branch 'unstable' of github.com:Neverlord/libcppa into unstable
Merge pull request #104 from mavam/unstable

Tweaks to optional<T> to comply with the interface of std::optional<T>.
moved operator+(spawn_options) to cppa namespace

this patch fixes an issue with argument-dependend lookup and
anonymous namespaces
changed version to 0.8
override chained_enqueue in threaded impl

this patch fixes a bug with chained_enqueue, i.e., chained_enqueue
was called on scheduled_actor instead of threaded
added test for detached actors
allow actors to respond by returning values
fixed compiler error regarding auto
fixed paths in Doxyfile
changed semantic of `quit`, deprecated reply

this patch changes the semantics of `quit` slightly,
i.e., `quit` always guarantees that all currently running message
handlers are executed and the given exit reason is not applied
until `on_exit` ran an did not set a new behavior;
this patch also deprecates `reply`, because the recommended way
of replying to a message is to return the value from the
message handler
removed 'virtual' wherever 'override' is used
got rid of 'reply is deprecated' warnings
Merge branch 'unstable' of github.com:Neverlord/libcppa into unstable
manual update for upcoming version 0.8
added new exit reason `user_shutdown`
updated strongly typed actors

this patch:
- unifies handling of response messages for typed and `untyped` actors
- adds class-based typed actors
- updates the manual to cover the latest implemenetation of typed actors
- adds the exit reason `user_shutdown`
fixed monitoring of remote actors

this patch ensures that local actors will receive exit and down
messages for remote actors correctly