Make sure the parser is safely compatible with old
resources format -- for those users still using
custom resources (via `userResourcesLocation`).
Prepare code for future fix to
<https://github.com/uBlockOrigin/uBlock-issues/issues/156>:
This commit introduces a new private Map() object,
`uBOSafe`, accessible by all injected scriptlets. This
private safe can be used to store data which can be shared
with different scriptlets. The idea is for scriptlets to
use that safe to graciously deal with the need to install
multiple listeners for the same property.
With hindsight, I revised decisions made earlier during
this development cycle:
Un-redirectable scriptlets have been removed from
/web_accessible_resources and instead put in the new
/assets/resources/scriptlets.js, which contains all
scriptlets used for web page injection purpose.
uBO will no longer fetch a remote version of built-in
resources.
Advanced setting `userResourcesLocation` will still be
honoured by uBO, and if set, will be fetched every
time at least one asset is updated.
