workaround issue 9634
Issue 10265 - RandomSample fails when passed an InputRange as input

 * Issue fixed by making presence of save() property conditional
   on input being a ForwardRange.
Unittests for randomSample being passed an InputRange.

The assignment of _input = input has been moved from
initialize() to the constructors so as to avoid
problems with nested structs.
Merge pull request #1334 from denis-sh/improve-Issue-10220-fix

Improve Issue 10220 fix.
Merge pull request #1290 from blackwhale/regex-9634

Workaround issue 9634
Merge pull request #1332 from WebDrake/randomsample-save

Issue 10265 - RandomSample fails when passed an InputRange as input
fix Issue 10268 - std.typecons.Nullable!JSONValue - error instantiating
Merge pull request #1340 from 9rnsr/fix10268

[REG2.063] Issue 10268 - std.typecons.Nullable!JSONValue - error instantiating
Add some static array traits

* adds `staticArrayDims`
* adds `MultiDimStaticArrayElementType`
* adds `multiDimStaticArrayElementCount`