Properly fix linking QtMain on windows

CMake policy CMP0020 (that since CMake 2.8.11 automatically links
QtMain target when set to NEW for WIN32 targets) was discarded because
set in the YarpUseQt5 file.

The "cmake_policy" call is now in the main CMakeLists, so that it is
automatically used in all the project.
Fix CMake warnings caused by qt5_use_modules macro

The macro is now hidden on CMake 2.8.11 or later, by the one defined in
YarpUseQt5.cmake, that just calls target_link_libraries instead.
Cleanup
Replace deprecated OUTPUT_PATH variables with OUTPUT_DIRECTORY equivalents

This time do not use per-config variables, but let CMake handle them.

DLLs are considered "RUNTIME" on windows, and therefore, from this patch,
they will end in the "bin" directory. Therefore install commands are update
to reflect this change.
Fix Qt5 executables and plugins

The path is now different for build-tree and install-tree for multi
config generators, but the executables now import both paths.
Fix "Policy CMP0020 is not known to this version of CMake" error on CMake < 2.8.11
[bindings] add missing base class that was obscuring RpcClient::open

Swig didn't know how to AbstractContactable. Fixes #233.
Thanks @arocchi!
respect # and // in ini files, fixes #236
Merge pull request #234 from drdanz/OUTPUT_DIRECTORY

Update variables and fix Qt5 executables
Restore gyarpmanager and gyarpbuilder executables

Fixes #235
do not add gtkdatabox+goocanvas without GTK2, fixes #237
[doc] add information about yarp::os::NameSpace
Merge pull request #240 from paulfitz/no-gtk2

do not add gtkdatabox+goocanvas without GTK2, fixes #237
[doc] internals of yarp::os::MultiNameSpace
Suppress warning when Qt5 is not available
Update .mailmap file
Fix missing qmldir files on non-multi-config generators
Fix typo in configure_file command
allow namespace to be configured externally as local
add optional timeout to FakeBot for testing purposes