Fixs bug in set-version! and added sandbox option

Fixes a bug in the set-version! function that sets the +version+ atom
to an atom containing the version value instead of the value.  Also
adds a option to use the sandbox (aka test.salesforce.com) for login.
Merge pull request #8 from ahjones/master

URL encode the SOQL query string
Merge pull request #7 from dwelte/master

Fixs bug in set-version! and added sandbox option
bump version