Additions to the i2ocore : user space access

We are looking at several additions in to the i2ocore here :

1. We can add support for the mapping of some memory area in userspace (quite simple), in order to have the ability to write a user space library for prototyping. (xdaq-shell)
2. We can add some xdaq-shell calls to have read-writes actions in drivers (currently, only a message passing scheme is possible, through ioctls)
3. We can add a default i2ocore module that allows generic read-writes to PCI bus (io, memory, config) from user space. (This is baded on the API from christoph

Christoph's library documentation is at : http://cmsdoc.cern.ch/~cschwick/software/documentation/hardware/generic/html/