Import debugStream library from icub-main

This patch introduces some new logging macros:

`yTrace`
`yInfo`
`yDebug`
`yWarning`
`yError`
`yFatal`

The new version of `yarp/os/Log.h` allows to use the "printf-like" version of the macros

```C
#include <yarp/os/Log.h>
int i = 13;
yDebug("This is %s (%d)", "a debug", i);
```

The new header file `yarp/os/LogStream.h` allows to use the "stream-like" version of the macros (and also the "printf-like" version

```C++
#include <yarp/os/LogStream.h>
int i = 13;
yDebug("This is %s (%d)", "a debug", i);
yDebug() << "This is" << "another" << "debug" << i;
```

`yarp::os::impl::Logger` class is still used internally but can be removed in another moment.

Also add the `yAssert` macro that replaces YARP_ASSERT and bump tweak number.