Make Coins.AllGT() more robust and consistent

[sunnya97]

• Targeted PR against correct branch (see CONTRIBUTING.md)

• Linked to github-issue with discussion and accepted design OR link to spec that describes this work.

• Wrote tests

• Updated relevant documentation (docs/)

• Added entries in PENDING.md with issue #

• rereviewed Files changed in the github PR explorer

---

For Admin Use:

• Added appropriate labels to PR (ex. wip, ready-for-review, docs)
• Reviewers Assigned
• Squashed all commits, uses message "Merge pull request #XYZ: [title]" (coding standards)

[alessio]

Please have a look at my implementation in #3678

// IsAllGT returns true if for every denom in coins, the denom is present at a
// greater amount in coinsB.
func (coins Coins) IsAllGT(coinsB Coins) bool {
	if len(coins) == 0 {
		return false
	}

	if len(coinsB) == 0 {
		return true
	}

	if !coins.ContainsDenomsOf(coinsB) {
		return false
	}

	for _, coinB := range coinsB {
		amountA, amountB := coins.AmountOf(coinB.Denom), coinB.Amount
		if !amountA.GT(amountB) {
			return false
		}
	}

	return true
}

[codecov]

Codecov Report

Merging #3820 into develop will increase coverage by 0.01%.
The diff coverage is 100%.

@@             Coverage Diff             @@
##           develop    #3820      +/-   ##
===========================================
+ Coverage    60.93%   60.94%   +0.01%     
===========================================
  Files          192      192              
  Lines        14328    14342      +14     
===========================================
+ Hits          8731     8741      +10     
- Misses        5028     5031       +3     
- Partials       569      570       +1

[alessio]

ACKing Sunny's changes

[rigelrozanski]

I dig the DenomSubset approach

[cwgoes]

Several questions on implementation and comment/code mismatches.

[cwgoes]

Fails test_cover, looks like, and needs PENDING.md comments resolved.

[alessio]

@cwgoes

E[2019-03-12|15:08:37.960] Stopped accept routine, as transport is closed module=p2p numPeers=0
--- FAIL: TestBonding (5.05s)
	Error Trace:	lcd_test.go:557
	Error:      	Not equal: 
	            	expected: 30000000.000000000000000000
	            	actual  : 29700000.000000000000000000
	            	
	            	Diff:
	            	--- Expected
	            	+++ Actual
	            	@@ -1,2 +1,2 @@
	            	-(types.Dec) 30000000.000000000000000000
	            	+(types.Dec) 29700000.000000000000000000
	            	 
	Test:       	TestBonding
LADDR tcp://0.0.0.0:46464