Report caching

A report and its data can be cached both in memory (to increase speed) and in a file on disk (to reduce RAM usage). There are several types of caching in Fast Report:

- “TfrxReport.EngineOptions.UseFileCache” - when True the whole text and objects of a built report are saved in a temporary file on disk; “TfrxReport.EngineOptions.MaxMemoSize” sets how many MB are reserved for the report in RAM

- “TfrxReport.PreviewOptions.PagesInCache” -  the number of pages which can be kept in cached memory, which greatly increases preview speed,  but uses a lot of memory (especially if there are pictures in the report)

- “TfrxReport.PreviewOptions.PictureCacheInFile” - when True all pictures in a built report are saved in a temporary file on disk, which greatly reduces memory use in reports that have a large number of pictures; but it reduces the speed