serialcheck: add version 1.0.0

Simple serial tester

Usage (as explained in Readme.txt, part of ${PN}-doc package):
 - Create a random file.
   dd if=/dev/urandom of=binary count=1 bs=4096

 - Copy the random file to both nodes.

 - Start the test
   receiving node:
        serialcheck -d /dev/ttyS0 -f binary -m r -l 10

   sending node:
        serialcheck -d /dev/ttyUSB0 -f binary -m t -l 10

   Start the receiving side before the sending side. This will transfer the
   "binary" file 10 times and the other side will expect the file 10 times.
   Once the program completes both sides should write something similar to:

|  Needed 0 reads 1 writes loops 10 / 10
|  cts: 0 dsr: 0 rng: 0 dcd: 0 rx: 0 tx: 40960 frame 0 ovr 0 par: 0 brk: 0 buf_ovrr: 0

   and in error case the receive side:

Needed 20 reads 0 writes Oh oh, inconsistency at pos 2273 (0x8e1).
Original sample:
000008b0: 28 b2 18 c9 ec b5 2c b3  3a a1 29 b1 fc 27 20 7f   (.....,.:.)..' .
000008c0: 42 f8 d5 cb d8 52 ec b5  c8 76 d3 4b d2 57 44 6a   B....R...v.K.WDj
000008d0: 40 81 6a 82 27 fd 8d 50  84 70 bc 24 6b 3d 88 fd   @.j.'..P.p.$k=..
000008e0: 9f ac 78 a4 76 9b f9 1c  74 2c d6 79 22 60 c5 de   ..x.v...t,.y"`..
000008f0: 02 9c fb 52 21 4b 40 6f  80 69 2e 80 df 12 ba a0   ...R!K@o.i......
00000900: 75 57 d5 22 33 c0 f3 bc  94 f8 aa 22 9d 02 59 20   uW."3......"..Y

Received sample:
000008b0: 28 b2 18 c9 ec b5 2c b3  3a a1 29 b1 fc 27 20 7f   (.....,.:.)..' .
000008c0: 42 f8 d5 cb d8 52 ec b5  c8 76 d3 4b d2 57 44 6a   B....R...v.K.WDj
000008d0: 40 81 6a 82 27 fd 8d 50  84 70 bc 24 6b 3d 88 fd   @.j.'..P.p.$k=..
000008e0: 9f 00 ac 78 a4 76 9b f9  1c 74 2c d6 79 22 60 c5   ...x.v...t,.y"`.
000008f0: de 02 9c fb 52 21 4b 40  6f 80 69 2e 80 df 12 ba   ....R!K@o.i.....
00000900: a0 75 57 d5 22 33 c0 f3  bc 94 f8 aa 22 9d 02 59   .uW."3......"..Y
loops 54878 / 4294967295

cts: 0 dsr: 0 rng: 0 dcd: 0 rx: 224792017 tx: 223379456 frame 0 ovr 1 par: 0 brk: 0 buf_ovrr: 0

Signed-off-by: Denys Dmytriyenko <denys@ti.com>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>