lispy.el: Release 0.27

Fixes #479

Make "O" work for vectors

* lispy.el (lispy--oneline): Update.

* lispy-test.el (lispy-oneline): Add test.

lispy.el (lispy-goto-symbol): Simplify

* lispy.el (lispy-goto-symbol): Just use `geiser-edit-symbol'.

* le-scheme.el (lispy--scheme-goto-symbol): Remove.

Improve "g"

* lispy.el (lispy-build-semanticdb): Return the corresponding db.
(lispy--fetch-tags): Try to call `lispy-build-semanticdb' before raising
an error.

Completion methods aplenty

* lispy.el (lispy-completion-method): New custom var.
(lispy--tag-name-and-file): Give only a plain name for `ido', unless
`ido-vertical-mode'.
(lispy--select-candidate): Dispatch on `lispy-completion-method'.

You can now jump to tags with:

- helm
- ido
- ido-vertical
- icomplete-mode
- icy-mode
- plain-old completing-read

Fixes #44.

lispy.el: remove obsolete aliases

Rename -out-forward to -right, and -out-backward to -left

* lispy.el (lispy-out-forward): declare obsolete in 0.21.0.
(lispy-out-backward): declare obsolete in 0.21.0.
(lispy-out-forward-nostring): declare obsolete in 0.21.0.

lispy.el: bump version

lispy.el: bump version

README.md: add demo 3