A lot of changes...

.. ntag simulation stuff from @marshmellows branch "ntag/sim"
.. hf mf mifare fixes from @pwpivi.
.. hw status command
.. speedtest function from @pwpivi
.. Viking Functionalities,   (not a proper DEMOD, but a start)
.. GetCountUS  better precision from @pwpivi
.. bin2hex,  hex2bin  from @holiman

...
starting with getting the T55x7 CONFIGURATION_BLOCK for different clone situations. Ripped from Adam Lauries RFidler,   nothing working or finished..
...
Started working with the T55x7 read command with password actually performs a write block...  See Issue #136  https://github.com/Proxmark/proxmark3/issues/136    Not solved yet.

...
Started add SHA256..   not working yet..

client/Makefile

@@ -119,6 +119,7 @@ CMDSRCS = 	nonce2key/crapto1.c\
 			cmdlfem4x.c \
 			cmdlfhitag.c \
 			cmdlfti.c \
+			cmdlfviking.c\
 			cmdparser.c \
 			cmdmain.c \
 			cmdlft55xx.c \
@@ -130,6 +131,7 @@ CMDSRCS = 	nonce2key/crapto1.c\
 			aes.c\
 			protocols.c\
 			sha1.c\
+			sha256.c\
 			cmdcrc.c\
 			reveng/reveng.c\
 			reveng/cli.c\