Add two implementations split10 and split11

[rep-movsd]

split10

This is a simple implementation that uses std::find()

It uses a for loop with two variables:
itStart - iterator start of a word
itDelimiter - iterator to a delimiter

We get the result of find() for the next delimiter in itDelim and then
save the range (itStart, itDelim) as a token, and emplace the string into
the result vector

This very simple 5 liner shows that good C++ code can beat C code without
any trouble

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split11

Almost the same as split10 but we use a StringRef class just like the
one in split6. Instead of iterators we use a char pointer
This speeds it up by almost a factor of 80%

We get pretty close to the subparser version, only about 15% slower on my
system.

---

Benchmark results (trimmed output for 80 columns)

$ ./run_all.bash
=== System info
Arch rolling
Linux 4.5.5-1-ck x86_64 GNU/Linux
Intel(R) Core(TM) CPU X 920 @ 2.00GHz
g++ (GCC) 6.1.1 20160501
Python 3.5.1
=== End System info

./split.py Python: 38.9 seconds. Crunch Speed: 514293.2
./split5.py Python: 41.0 seconds. Crunch Speed: 488168.6
./split1 C++ : 8.7 seconds. Crunch speed: 2288344.6
./split2 C++ : 20.9 seconds. Crunch speed: 958164.2
./split6 C++ : 3.6 seconds. Crunch speed: 5603155.4
./split7 C++ : 2.6 seconds. Crunch speed: 7750547.7
./split8 C++ : 31.0 seconds. Crunch speed: 644411.0
./split9 C++ : 21.1 seconds. Crunch speed: 949104.7
./split10 C++ : 3.7 seconds. Crunch speed: 5387448.0
./split11 C++ : 2.3 seconds. Crunch speed: 8703679.3
./split_subparser C++ : 2.0 seconds. Crunch speed: 9956735.4
./splitc1 C++ : 7.9 seconds. Crunch speed: 2519434.9
./splitc2 C++ : 8.0 seconds. Crunch speed: 2484935.2
./splitc3 C++ : 8.0 seconds. Crunch speed: 2515293.7
$