Storing/updating analysis information on disk

[vovapolu]

The current implementation stores all info in memory, this might lead to OOM errors and slow start of every analysis process for big projects.

The next step is to store all info on disk, read it partially before starting the analysis and update it when source files are changed. But there are several possible problems:

• Performance. Writing and reading from disk is much slower than from memory. It's quite possible that decrease of performance when working with disk could outweigh benefits.
• Caching. Change in one core file could lead to cache invalidation in many more files. Considering the decrease of performance when writing on disk it could lead to really slow updates of analysis results. This case are especially important for IDE support.