Fix Access Denied errors on Windows
Closes #907
Don't add binstar tokens in the config tests

Otherwise the normalization tests fail if the user is logged into binstar, as
the normalized url is different.
Check for rc_list_keys using argparse in conda config

Also add tests for invalid list and bool keys
Changes to conda config:

- Don't check list keys in argparse (it checks both the key and the item)
- Check for list keys that aren't actually lists in the .condarc (for now we
  give an error)
- Add a test for this case
Don't expect directories starting with conda- to be commands

Also, be defensive in calling not calling a command if it isn't found

Fixes #709.
No longer recommend to run conda init

Rather, we recommend to create conda environments. conda now works in an
uninitialized state, as long as you don't try to work in the root
environment.

Still todo is to hide the init command from conda --help.
Improved error message when directory can't be deleted
fix warning message
Merge pull request #909 from dhirschfeld/windows-rmtree-conservative

Fix Access Denied errors on Windows
Give special error message if binstar tokens are expired
Merge branch 'master' of github.com:conda/conda
Only check for the configured channel alias (without the token)
Fix typo
Hide the binstar token, and add a comment
Fix channel urls not showing with conda list, and remove the bare except that
was masking the bug