fixed timeout handling in become() API, fixes #116
This allows libcppa to compile and run on windows using g++ and MingW.
The examples and tests run. Remaining problems:
1. middleman_event_handler::update runs into "cannot erase " << ptr << " (no such element)" on disconnect of a remote actor.
2. chat example client crashes in windows on connect
backtrace just prints addresses.
added execinfo_windows.h for missing execinfo.h in mingw
uuid from disk partition now implemented.
cleaned up MinGW changes, removed node_id::get

this patch streamlines the recent patch from ajac: enforce consistent
coding style, removed the superfluous windows_tcp class and moved
the node_id::get to the MM, to guarantee WSAStartup has been called
before accessing network devices
fixed includes + minor issues in MinGW build
fixed group chat example
fixed warnings and remote tests in MinGW build
re-implemented companions + fixed Qt examples
removed channel::enqueue

this patch equalizes the interface of `channel` and `actor` by
removing the `enqueue` member function and providing `operator->`
instead to access the `enqueue` member function of the held pointer
directly
removed channel::enqueue

this patch equalizes the interface of `channel` and `actor` by
removing the `enqueue` member function and providing `operator->`
instead to access the `enqueue` member function of the held pointer
directly
Merge branch 'master' of https://github.com/Neverlord/libcppa
fixed channel implementation
fixed logging issues in OpenCL build, closes #119