Co-locate Votive file association custom actions.

The custom actions to set the latest Visual Studio version were in the
Votive product file but are only used by the file association code. This
commit brings them together in the file association code.
Allow share delete on get/set file timestamps.
Add TouchFile custom action.

New support for updating the modified date/time of a file.
Replace devenv /setup call with fast extension update mechanism.

The devenv /setup call when installing the WiX toolset can take minutes
to complete. Fortunately the VSIX installation method introduced
another way to complete the registration of extensions. All that is
necessary is to touch the "extensions.configurationchanged" file.
Minor code-review cleanup
Merge branch 'develop' of https://github.com/wixtoolset/wix4 into develop

Conflicts:
	History.md
WIXFEAT:4258 - complete introduction of access modifiers for identifiers.
Update WiX toolset to use access modifiers.
Merge pull request #22 from firegiant/feat4258-allids

WIXFEAT:4258 - complete introduction of access modifiers for identifiers.
Make WixBA Model.Version setter private based on code review feeback.
Be consistent in use of double quotes in WiX setup code.
Set the TouchFile attributes consistently in the UtilCompiler.
Only the lux.xsd Component is referenced so place the Id there.

The lux.xsd Component is referenced from the ComponentGroup because it
installs into a different folder. The previous commit placed the Id on
the File element incorrectly believing the file was referenced
elsewhere. Place the Id on the lux.xsd Component is more correct.
Merge pull request #23 from robmen/pr-cleanup

Integrate pull request feedback.