Fix typo in README.md
Merge pull request #13 from cmpitg/patch-1

Fix typo in README.md
Add Racket HEAD to the matrix.
Add missing deps and build-deps. Fixes #14.
Fix typo in comment.
Check for even number of items for {} dicts.

If odd number, raise a good syntax error message (instead of user
getting error from `alist` or `hasheq` or whatever `current-curly-dict`
is).

Note: The error message would be "excellent" not just "good" if I could
figure out how to make `raise-syntax-error` print using {} not ().
Merge branch 'master' of https://github.com/greghendershott/rackjure
Add installation instruction