Do not use versioned directory for YARP CMake config files

Fixes #159
[ros] add translation of duration type, see #161
Compile static libraries with -fPIC

Fixes robotology/qtyarp#5
Remove no longer needed explicit -fPIC

Since this is now enabled for all static libraries, it is no longer
needed to add it explicitly.
Enable shared libraries by default
[http] send hostname for virtual hosts when using http carrier
update default output of yarp conf (thanks @lornat75)
Link harness_os with the pthread library on linux

src/libYARP_OS/harness/PortCoreTest.cpp requires sem_destroy from
some include.
Update .mailmap file
Update generate-cmake-options script

* Always build gyarpbuilder (not just for experimental builds)
* Disable USE_PORT_AUTHENTICATION
* Reorder options and remove duplicates
changeLog updated