Google-images-search

- Google api search apgination using next searxh parameter (change suggested by [Uskompuf](https://github.com/Uskompuf)

- Sometimes google api desn't return 'items' in response and code breaks.

- Multithreaded images downloading
- Download progress bars
- External progress bar insertion

- Non-alphanumeric characters removed from file names which are not valid characters in windows file names (change made by [sebastianchr](https://github.com/sebastianchr)

- Code formatted.

- Cache_discovery option forward fix.