updated some inner workings
bugfix in the save content

(some regions were not saved if rel=page and you are editing the region from a sub-page or post)
added the MW_CACHE_EXPIRES constant

setting this constant allows you to control the cache expiration time
fixed some internal function mappings
bugfix in the add page layout selector
bugfix in the default options during install

the default options were not set during install
fix in the import_sql_file function
Merge pull request #98 from microweber/0.760

0.760