Tweaks for internal build

Merge branch 'vs_version_sniffing' of https://github.com/baronfel/visualfsharp into baronfel-vs_version_sniffing

Merge branch 'to_string_null_fix' of https://github.com/rojepp/visualfsharp into rojepp-to_string_null_fix

    This makes them available on the "tests" tab

commit 6af6e3fcb96b3a387a5f523520aba121637db7a3
Author: Samuel Bronson <naesten@gmail.com>
Date:   Sat Nov 14 12:15:12 2015 -0500

    Fix "Complier" -> "Compiler" in test output name

commit 8b86a440795695894985aa60629123729136a636
Author: Samuel Bronson <naesten@gmail.com>
Date:   Sat Nov 14 22:51:02 2015 -0500

    Add a note about "goto :EOF" to RunTests.cmd

commit 6d6b94dd6bfc9104a9cb015c4d6c80d358d34bdc
Author: Samuel Bronson <naesten@gmail.com>
Date:   Sat Nov 14 21:25:51 2015 -0500

    Tighten up tests/fsharpqa/testenv/bin/.gitignore

commit b43c986a2ba76f3ed7406523b688c3783e20e5c9
Author: Samuel Bronson <naesten@gmail.com>
Date:   Sat Nov 14 01:36:04 2015 -0500

    Add tests/fsharpqa/testenv/bin/nunit to .gitignore

commit 908b79cc716e34ffd100ccca0f4602e08e8b6f69
Author: Samuel Bronson <naesten@gmail.com>
Date:   Sat Nov 14 17:14:12 2015 -0500

    Send MSBuild output to AppVeyor

    I did this because I was getting tired of waiting for entire
    twenty-minute builds every time I wanted to see if I'd gotten the
    test-result uploading right yet.

    It didn't give me a whole lot to do while I waited, since it actually
    worked the first time, but on the other hand that was also the time I
    finally got the result uploading to work, so it didn't really matter.

commit 9cd11904a0e1fe6211eb904284fc46b38e4648ef
Author: Samuel Bronson <naesten@gmail.com>
Date:   Sat Nov 14 16:25:05 2015 -0500

    appveyor-build.cmd: Fix failure to properly fail

    We should always return a failure code when exiting due to an error.

fix appveyor build badge of master branch

revert to run only a reduced set of tests

the target was branch fsharp4

Merge branch 'tests_suite_with_nunit' of https://github.com/enricosada/visualfsharp into enricosada-tests_suite_with_nunit

Add links to DEVGUIDE and TESTGUIDE

Sigh!!!! .... it was missing the links.

Inline "Required Tools for Windows Development and Testing"

- set the env var FSHARP_TEST_SUITE_USE_NUNIT_RUNNER
- run same fsharp suite like before ( 'RunTests.cmd debug fsharp` )

include/exclude tags works ( RunTests.cmd debug fsharp Smoke )

the output is:

- tests/TestResults/FSharpNunit_Output.log
- tests/TestResults/FSharpNunit_Error.log
- tests/TestResults/FSharpNunit_Xml.xml

skip this commit on merge

add nunit tests to run Cambridge test suite ( tests/fsharp )