binding => topBinding so that partial Bundles work and undefined Bundle members properly forward to DontCareBinding

This shows errors comparing literals

Provide direct conversion from ChiselIR to FIRRTL.
Provide Driver support for dumping ProtoBuf.

Resolves #841

Signed-off-by: Schuyler Eldridge <schuyler.eldridge@ibm.com>

Documentation for example had parameters in wrong order, and was missing @param. Additionally, it was lacking a module wrapper. This has been corrected.

Add chisel3.experimental.IO for programmatic port creation in Raw and
MultiIOModules. suggestName is required to name ports that cannot be
named by reflection. Two ports cannot be given the same name.

Move common code into CommonBuild.sc
Remove extra ThisBuildInfo trait
Override publishXmlDeps() to avoid generating a self-dependency (since our dependent modules don't really have their own identity and end up duplicating PublishChiselModule

 - need to specify mainClass - mill should figure it out on its own
 - manifest isn't complete
 - javaDoc is missing version info, some javascript, and differs from sbt generated javaDoc, but it doesn include core and internal documentation
 - ivys are missing description, configurations, scala dependencies
 - poms use artifactId for name (instead of descrption), license is BSD-3-Clause, developer is missing url, dependencies are missing scala dependencies, but include a dependency on the library itself(!).

Still some problems building source and doc jars, largely due to relative paths.