Work items for CLI port/unblock OneASP.NET consumption

[mlorbetske]

Engine improvements

• Support lookaround operators Allow prefixes/suffixes in tries/create a way to express non-included prefixes/suffixes on symbol declarations #63 (enables better comment support in XML-like documents)
• Support for importing remote resources Create conditionally valued symbols/allow sourcing symbol values from other places #62 (enables selecting trains for .NET Core Projects)
• Parameter validation Solidify types, support presence => true style parameters #65 (better experiences around selection, could enable bash completion)
• Allow blocks to be unprefixed when processing conditions Modify the "conditional" operation or create a new operation that handles un-prefixing matched blocks #56

Migration blockers (required to complete #57)

• Fix component load Fix the way components are loaded #61
• Ensure dependencies are correct at install time Walk the NuGet graph during install #60

VS Integration Requirements

• Figure out how to express pivots and classifications Solidify the notion of pivots/tags #58 and Add template hierarchy support #47
• Make sure that all required metadata is expressed Plumb through extension metadata #53
• Solve the issue of conflicting component requirements Provide some way of being able to isolate components when loaded in the context of VS #66

Authoring Improvements

• Allow templates to be packaged as part of tooling Create packaging utility #54 (VS, XS?)
• Allow templates to advertise group membership Provide some sort of a non-collapsing grouping mechanism #64