* module/language/scheme/spec.scm (scheme): Specify an evaluator, `eval'.
* module/system/repl/common.scm (repl-default-options): Add option,
`interp', specifying that, if possible, the repl should interpret its
expressions rather than compile them. Defaults to #f.
* module/system/base/syntax.scm (keywords): Don't enable :keywords, it
breaks code that may assume that ':foo is a symbol, like boot-9.
* module/*.scm: Don't use :keywords, use #:keywords. The user can decide
if she wants #:keywords in their .guile, and :keywords might make us
compile modules differently.
