Moving global settings for crengine to ./data/cr3.ini

1. On making "dummy" document, crengine will try to read & apply settings from ./data/cr3.ini. If it finds nothing (say, at first run), it will create this file with default values so that users may manually edit any included parameter.
2. Function to save global defaults for crengine - saveDefaults. One may call this function either i) on the user's manual request or ii) everytime just before crengine closes document (so crengine will remember last configuration)