Fix memory leaks

[Arooba-git]

Hello 👋
As part of our project, we are using Facebook's new Memlab tool to detect memory leaks in SPA applications.
While running the tool and analyzing the code of defichain-income, we saw that your project does a very good job of ensuring that all async operations are cancelled when the component is destroyed. However, as per Memlab execution results, we found a dangling subscription and some timers that were causing the memory to leak (screenshots below).

[before]

Hence we added the fix by unsubscribing the subscription and clearing the timers in component destructors, and you can see the heap size and # of leaks reducing noticeably:

You can analyze this and other potential leak sources, if you like, by running Memlab with a scenario file covering the maximum # of use cases.
Following is a sample of the scenario file we used (it needs to be a .js file but attaching here in .txt form):

deficiain-memlab-scenario.txt

Note that some other reported leaks (in Memlab) originated from Angular's internal objects, and hence were ignored.

[Arooba-git]

bump @rogi-sh