Removing memleaks + more options for the Utils

[andrija-hers]

Majority of the proposed PR deals with proper handling of variables so that the garbage collector can easily do its job.

Besides the memleak-removal stuff, we added 2 more options for the Utils instance:

1. nocache - if true-ish, then the Utils instance will not cache anything (especially important for the case of saving the response from superagent, that leads to heavy memory consumption)
2. timeout - if present, it will be used against the superagent Response, so that problematic links do not take too long to complete