Internal tools, externalized

[adamyg]

Review standalone instances, mcedit, mcdiff and mcview.

Options:

• links; yet can be problematic with some Win environments.
• application stubs; redirect to mc.

Note: rename mcdiff (build-230) to mcbsddiff

[yehorb]

I am unaware of the context for this issue, but I suggest you consider shims as an alternative to links. For example, this shim solution is used by default in Scoop. I use Scoop and shims it provides daily, and I find them to be very stable and completely transparent from the UX perspective.