Instead of doing a 'go list' call every time we need to fetch a
dependency's export file, we now do a single 'go list' call before the
build begins. With the '-deps' flag, it gives us all the dependency
packages recursively.
We store that data in the gob format in a temporary file, and share it
with the future garble sub-processes via an env var.
This required lazy parsing of flags for the 'build' and 'test' commands,
since now we need to run 'go list' with the same package pattern
arguments.
Fixes#63.
Daniel Martí
lu4p