Be less strict in enabling the Database and Editor menus

Fixes #44
Days 29-31 are never allowed by these rules
Display correct warnings for basic rules

Also fix several 80-character lines
Fixes #159
Always enable Save/Close/Apply all menu actions

Fixes #182
Init static modules folder
Include TextUrlCtrl class statically

Fixes #184
Preserve database order when restoring session

Fixes #188