* Source packages improvements

* Target net45

* Only generate source link when emitting PDBs

* Make BuildBoss happy

Ensure-DotnetExe should be Ensure-DotnetSdk.

This enables the generation of binary logs for our build when running in Microbuild.
Having the logs available helps in post-build debugging of errors. We tend to get a
number of microbuild only failures that are impossible to track down without logging
like this.

Once this is merged i will be adding a task to our VSTS build definition to publish
these post build.

These were moved in https://github.com/dotnet/roslyn-sdk/pull/21

The assembly name of the deployment project was clashing with the ilasm
exe we were trying to deploy. Gave it an explicit name to remove the
clashing values.

Our project files are now a mix of empty XMLNS and official MSBuild
XMLNS. BuildBoss needs to handle both cases.

The combination of the minified MSBuild syntax and Directory.Build.props
/ targets file will change when in the build process our central build
files are executed. For instance Imports.targets will now be run much
later in the build after Sdk.targets. Where before, when it manually
invkoed Sdk.targets it was able to run both before and after it.

To keep our build functioning the same way we need to move around some
of the logic within our build files so that it executes in the same
relative order as it did before

It had conflicting TargetFramework and OutputType annotations

Related to https://github.com/dotnet/roslyn/issues/23566.

We've basically forced all projects to use the SDK approach to
localization, but this project doesn't use the SDK. As a result, it
doesn't produce satellite assemblies, and the build fails when we try to
copy the non-existent files to the output directory.

For the moment, just turn off XLIFF-based localization.

The imported build tasks targets sets a nonexistent default target

This enables the generation of binary logs for our build when running in Microbuild.
Having the logs available helps in post-build debugging of errors. We tend to get a
number of microbuild only failures that are impossible to track down without logging
like this.

Once this is merged i will be adding a task to our VSTS build definition to publish
these post build.

This check existed to verify that the two lists of compiler files was
kept in sync. Now that there is only one list there is no reason to run
the check anymore.

It's gross, but we need to publish *something* until ILAsm is exposed as
a normal assembly

Also remove osx RID version

Remove the assembly version plumbing as it's no longer needed by our
build.