Change command line option name from cache to work

[berland]

The command line option cache hints to komodo supporting some kind of caching, which it does not. The directory named used as a cache is a working directory used while building, and cannot be prepopulated.

[kwinkunks]

Good stuff -- this is much needed!

Wondering if this PR should just take on #294 ? I wasted a bunch of time figuring it out a few weeks ago (and failing!) and I'm guessing you (and Julius/Zohar I think) just burnt a bunch more time figuring it all out again. Maybe a sign that we can no longer afford this particular bit of debt.

I guess I'm especially wondering if it's a good idea to introduce more words (work and workspace_for_downloads) especially as we already have workspace, which is something else again? Maybe download_directory is clearer?

[berland]

Yes. I even discovered the "workspace" option after having written this. "workspace" could possibly be the only allowed argument, and we can require it to be empty.

[kwinkunks]

I like this, much cleaner.

[kwinkunks]

Oh, I guess style is failing, but I'm sure you'll fix that :D