update LICENSE.txt

LICENSE.txt

@@ -1,12 +1,40 @@
-`bfe` is in the Public Domain.
+As a work of the United States government, this project is in the
+public domain within the United States.
 
-http://creativecommons.org/publicdomain/mark/1.0/
+Additionally, we waive copyright and related rights in the work
+worldwide through the CC0 1.0 Universal public domain dedication.
 
-**NOTE:**  `bfe` includes or depends on software from other open source projects, all or 
+## CC0 1.0 Universal summary
+
+This is a human-readable summary of the [Legal Code (read the full text)](https://creativecommons.org/publicdomain/zero/1.0/legalcode).
+
+### No copyright
+
+The person who associated a work with this deed has dedicated the work to
+the public domain by waiving all rights to the work worldwide
+under copyright law, including all related and neighboring rights, to the
+extent allowed by law.
+
+You can copy, modify, distribute and perform the work, even for commercial
+purposes, all without asking permission.
+
+### Other information
+
+In no way are the patent or trademark rights of any person affected by CC0,
+nor are the rights that other persons may have in the work or in how the
+work is used, such as publicity or privacy rights.
+
+Unless expressly stated otherwise, the person who associated a work with
+this deed makes no warranties about the work, and disclaims liability for
+all uses of the work, to the fullest extent permitted by applicable law.
+When using or citing the work, you should not imply endorsement by the
+author or the affirmer.
+
+### Dependencies
+`bfe` includes or depends on software from other open source projects, all or 
 most of which will carry their own license and copyright.  The Public Domain mark 
 stops at `bfe` original code and does not convey to these projects.
 
-
 --------------------------------------------------------------------
 
 The license below applies to the following dependencies:
@@ -68,4 +96,4 @@ DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
-SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.