ARROW-1491: [C++] Add casting from strings to numbers and booleans

[pitrou]

The implementation for numbers uses C++ istringstream. This makes casting a bit lenient (it will probably accept whitespace).

This is a rewrite of #1387

[codecov-io]

Codecov Report

Merging #2362 into master will increase coverage by 2.21%.
The diff coverage is 100%.

@@ Coverage Diff @@## master #2362 +/- ##
==========================================
+ Coverage 84.66% 86.87% +2.21% 
==========================================
Files 293 237 -56 Lines 45324 42705 -2619 ==========================================
- Hits 38372 37099 -1273 + Misses 6911 5606 -1305 + Partials 41 0 -41

Impacted Files	Coverage Δ
cpp/src/arrow/compute/kernels/cast.cc	91.54% <100%> (+1.67%)	⬆️
cpp/src/arrow/compute/compute-test.cc	99.54% <100%> (+0.05%)	⬆️
rust/src/buffer.rs
rust/src/memory_pool.rs
go/arrow/type_traits_boolean.go
go/arrow/math/int64_sse4_amd64.go
go/arrow/array/boolean.go
go/arrow/math/int64_avx2_amd64.go
go/arrow/math/int64.go
rust/src/error.rs
... and 48 more

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[cpcloud]

I sometimes wonder what the meeting was like that decided names like this.

[pitrou]

I had the same thought :-)

[cpcloud]

Can we make this a little more readable by use tolower?

[pitrou]

tolower is locale-dependent.

[wesm]

Thanks for this. Made a small comment about reusing type traits but otherwise OK by me

[wesm]

You could use enable_if_number<O> here from arrow/type_traits.h

[pitrou]

Done.

[pitrou]

Some weird failure occurred on the AppVeyor build that didn't occur on my AppVeyor account:
https://ci.appveyor.com/project/pitrou/arrow/build/1.0.570

[pitrou]

I want to make sure the AppVeyor failure was sporadic so I've triggered another build by pushing again.

[wesm]

rebased

[wesm]

+1