Flex Pages: Frontend issues with plugin events (changes do not stick)

[mahagr]

Due to differences in how the pages are cached, plugins making changes to the page objects during the events: onBuildPagesInitialized, onPageProcessed and onFolderProcessed will not be cached right now, causing the changes to be lost on later requests.

This issue needs to be solved as soon as possible.

[rhukster]

Not sure if all these event issues are based in the same fundamental problem, but onPageProcessed is used extensively. The other 2 not as much.

[mahagr]

The fix from above calls onPageProcessed every time a page is accessed first time during the request. While not ideal, it seems to fix most of the issues with plugins.

I still need to figure out how to efficiently cache the changes made by plugins.