Version 0.0.47

* Added new functionality to CMS module
* Added Core and CMS database SQL scripts impress.core.schema.sql and
impress.cms.schema.sql compiled from corresponding .js schemas by method
db.schema.mysql.generateScript
* Added SQL statements debug logging
* Added flag res.impress.cachable, it can be set by CMS or js handlers
(e.g. get.js, request.js...) to cache rendered pages in memory like we
cache static files