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
Do not use versioned directory for YARP CMake config files

Fixes #159
[ros] add translation of duration type, see #161
Merge pull request #160 from drdanz/position_independent_code

Compile static libraries with -fPIC and 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
Merge branch 'portaudio_rec_test' of https://github.com/robotology/yarp