TRACKING: exclusion implementation

[mixmix]

Issues:

• Loop member re-addition on exclusion #70
• Test being removed from a group #71
• Test staying in a group when someone else removes someone #72
• Test getting added to the group after the first epoch, but still getting access to all the epochs #76
• Adapt listMembers to exclusion #77
• Test getting added to an old epoch but still finding the newer epochs we've been re-added to #86
• Test getting excluded, reinvited, joining a group again #89
• Test restarting client after getting excluded. Will we try to rejoin old epochs? #90
• lib/epochs (getPreferredEpoch - 4.5. subset membership) #113
• lib/epochs (getPreferredEpoch - 4.6. overlapping membership) #114
• lib/epochs (getPreferredEpoch - 4.7. disjoint membership) #115

PRs:

• Re-enable checking of add-member spec #58
• Member tangle #64
• Basic member exclusion flow #65
• Update members tangle calculation for exclusion spec #75
• People not removed in an exclude should be able to post on the new epoch #78
• lib/epoch - getEpochs #83
• lib/epoch - getMembers #84
• Publish re-ad messages on the additions feed #85
• Add test for being removed from a group #88
• Epoch check missing members #91
• lib/epochs tieBreak #92
• Test being added to an old epoch #94
• extract lib/operators #97
• Promise.all setup/teardown in tests #98
• lib/epochs preferredEpoch case 4.4 (2 epochs) #99
• refactor epochs to consolidate getPreferredEpoch #104
• replace group/exclude with group/exclude-member #105
• People added late to a group should get access to all epochs #106
• Test adding someone back into the group #111
• preferredEpoch (live) now emits on membership updates #112
• 4.4 tidyup #121
• getPreferredEpoch case 4.5 - subset membership #122
• extract createNewEpoch #129
• Be more forgiving in getPreferredEpoch stream #134
• 4.6 overlap membership #140
• 4.7 split membership #141

[mixmix]

DONE! wow that was a lot 💥