Rename Show2 to Show, remove special casing of Parallelism=0 (not ready to merge yet)

@jklontz: we previously discussed this, but this branch drops the original Show, renames Show2, and removes special casing of parallelism=0

There are a few problems, the following transforms currently explicitly disable parallelism (and are blocked out in this branch) 
Edit
ElicitMetaData
Stasm
Of these, I guess ElicitMetaData and Stasm need to use a global lock since Elicit reads from stdin, and the stasm code is not thread safe. It should be possible for someone to reimplement Edit through Qt, similar to what was done with Show.

@sklum: thoughts?