Error catcher, ignore known errors

* Error catcher ignores var_export warning
Renderer, fix warnings

* Removed @ construct
File, basics

* Added basic file methods
* Added file copy
File hash, chunks

* Added min chunk size, 4096 kB
File saving

* Files can be saved, loaded, unloaded, etc
* Dropped deprecated function save_content
File temp

* Files can be put into temporary dir
* Temporary files are dropped on __destruct
* Recreated file fetching - file stays in memory
File class, docs
Temp files, keep

* Temporary files can be kept using keep attribute
Thumbs

* Separated thumbs from images to increase readability