Use os.walk for recursing+add ignored dirs

[Elias481]

This is a quite properly implemented merge of #30 from @Larivact + #31 from @innlym + #48 from @xlotlu into master. Would be fine if You could merge this or similiar as I dislike the idea staying on a fork not in sync with upstream to have a working version. (Still some fixes/cahnges missing here as I did not merge this proposal into my main fixes branch yet.)

[coveralls]

Coverage increased (+0.5%) to 85.616% when pulling 2fe0df69af7531ba4440a25785be772827ebcdb3 on Elias481:use-os.walk-for-recursing+add-ignored_dirs into 288a2b01fd4a726dc68d960f8351630aee788a13 on dsoprea:master.

[codethief]

Any news regarding this pull request?

[Elias481]

@codethief sadly @dsoprea seems busy with other things... I also didn't continue, partly because I waited for feedback and partly because the project I wanted to use this is on-hold for different reasons.

I wanted to merge all the collected fixes and changes into one branch and into one complete PR (so that at least I have a more complete version to continue with). I think I stopped somewhere with trying to get tests relyiably working on all the different kernels where inotify is available but changed somehow... For my part I will take a look into this soon.

[dsoprea]

This is too big of a PR. Please squash.