cmd/llgo-dist: Build packages listed by "go list std".

Keeps a "badPackages" list with a issue number reference on all packages
that currently do not build.

Dummy .ll files added to various packages just to get those packages building.
cmd/llgo-dist: Remove TODO comment regarding go list std ;)
Use Object.Pkg() everywhere

Packages are recorded correctly for imported
objects in go/types now, so we can do away
with the Package field from ObjectData. Also,
we can drop the pkgmap from TypeStringer.

Fixes #56
Fixes #62
Merge branch 'master' of github.com:axw/llgo
Merge pull request #74 from quarnster/master

cmd/llgo-dist: Build packages listed by "go list std".