This will hopefully reduce the false reports due to some unreliable hosters.
* Fixes broken links in memory_management/README.md
* Fixes broken link in audio_comp_sci/README.md
* Fixes broken link in security/README.md
* Fixes broken links in garbage_collection/README.md
* Increase max retries for lychee
* [A Unified Theory of Garbage Collection](https://researcher.watson.ibm.com/researcher/files/us-bacon/Bacon04Unified.pdf)
* [A Unified Theory of Garbage Collection](https://web.eecs.umich.edu/~weimerw/2012-4610/reading/bacon-garbage.pdf)
* [Teaching Garbage Collection without Implementing Compilers or Interpreters](https://cs.brown.edu/~sk/Publications/Papers/Published/cgkmf-teach-gc/paper.pdf)
* [Message Analysis Guided Allocation and Low Pause Incremental GC in a Concurrent Language](http://user.it.uu.se/~kostis/Papers/ismm04.pdf)
* [And Then There Were None: A Stall-Free Real-Time Garbage Collector for Reconfigurable Hardware](http://researcher.watson.ibm.com/researcher/files/us-bacon/Bacon12AndThen.pdf)
* [And Then There Were None: A Stall-Free Real-Time Garbage Collector for Reconfigurable Hardware](https://cacm.acm.org/magazines/2013/12/169948-and-then-there-were-none/fulltext)
* [The Slab Allocator: An Object-Caching Kernel Memory Allocator](https://www.usenix.org/legacy/publications/library/proceedings/bos94/bonwick.html)
* [A survey of coordinated attacks and collaborative intrusion detection (2010)](https://www.tk.informatik.tu-darmstadt.de/fileadmin/user_upload/Group_TK/zhou2010survey.pdf)
* [A survey of coordinated attacks and collaborative intrusion detection (2010)](https://www.sciencedirect.com/science/article/pii/S016740480900073X)
* :scroll: [Macaroons: Cookies with Contextual Caveats for Decentralized Authorization in the Cloud (2014)](macaroons-cookies-with-contextual-caveats.pdf)
* :scroll: [Insertion, Evasion, and Denial of Service: eluding network intrusion detection (1998)](ids-evasion-ptacek-newsham.pdf)