Add delete operation

[iwanbk]

Fixes #20

[codecov-io]

Codecov Report

Merging #22 into master will increase coverage by 1.65%.
The diff coverage is 92.3%.

@@            Coverage Diff             @@
##           master      #22      +/-   ##
==========================================
+ Coverage   84.61%   86.26%   +1.65%     
==========================================
  Files           7        7              
  Lines         260      284      +24     
==========================================
+ Hits          220      245      +25     
+ Misses         22       21       -1     
  Partials       18       18

Impacted Files	Coverage Δ
message.go	94.59% <100%> (+0.84%)	⬆️
bcache.go	86.48% <100%> (+0.37%)	⬆️
peer.go	82.71% <90.47%> (+5.68%)	⬆️
cache.go	91.3% <91.3%> (-1.92%)	⬇️

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[luisdavim]

Hi, if I understand correctly, you're not actually removing the keys from the cache, just marking them as deleted.

[iwanbk]

Hi, if I understand correctly, you're not actually removing the keys from the cache, just marking them as deleted.

Hi, you're correct, see #23 for the reason.