rename MakeValueTupleType --> MakeStructTupleType

revert 'use mutable' warning

project output will adapt to name changes

instead of needing to manually change the name of the xml file every
time the assembly name is changed.

Merge branch 'opt-editdistance' of https://github.com/jack-pappas/visualfsharp into jack-pappas-opt-editdistance

Merge branch 'optimize-path-chars-check' of https://github.com/jack-pappas/visualfsharp into jack-pappas-optimize-path-chars-check

List.scan/mapi2/map3 algorithm improvements

F# RFC FS-1020 - byref returns

try to reproduce async choice error revealed in #1378

Extend BuildTask to support dotnetcore

update to latest netfx build tools

Fix isTuple for arrays and pointers.