Mock Turtle Release v4.0.0 Beta 1

This has been tested intenrally. We would like to have other people
using it before releasing it

Mock Turtle Version 3.1.0

** [3.1.0] - 2018-03-09
This release brings in the gateware from wr-node-core repository, such as it
is being used in the released and deployed v1.0 version of masterFIP.
The relevant commit is 96a7859 from git://ohwr.org/white-rabbit/wr-node-core.git.
This is a "known to work" version of the gateware, still using the "node core" name.
Following releases will switch to the "mock turtle" name.

Mock Turtle 2.0.0

**[2.0.0] - 2016-06-08
*** Changed
- Project change name to Mock Turtle. this means renaming all files
  functions, data structures, enumerates and variables to a new
  convention
- port output real-time application to the real-time library
- improve kernel driver performance
*** Added
- unittest

Mock Turtle Version 3.0.0

** [3.0.0] [14-09-2017]
The realease of a new version has been necessary because I decided to remove
the debug interface from the API. This interface has been problematic, and
its original purpose has been neglected
*** Added
- standard TTY interface to access the soft-CPU serial console output
- minor improvements
*** Removed
- debugfs interface to access the soft-CPU serial console output
- removed library functions to access the debugfs console output
- the ``mockturtle-messages`` tool is not able anymore to access the soft-CPU
  serial console output
*** Fixed
- minor fixes

real-time library avaiable and used