support schema-api to return all schema of a graph

[zhoney]

Change-Id: I356336d46349bbc9ad42d7964013ea9147fdd986

[codecov]

Codecov Report

Merging #1567 (c73fea2) into master (634e4f9) will increase coverage by 0.14%.
The diff coverage is 100.00%.

@@             Coverage Diff              @@
##             master    #1567      +/-   ##
============================================
+ Coverage     63.14%   63.28%   +0.14%     
- Complexity     6673     6706      +33     
============================================
  Files           417      418       +1     
  Lines         34303    34451     +148     
  Branches       4740     4765      +25     
============================================
+ Hits          21660    21804     +144     
  Misses        10402    10402              
- Partials       2241     2245       +4     

Impacted Files	Coverage Δ
...ava/com/baidu/hugegraph/io/HugeGraphSONModule.java	82.88% <ø> (ø)
...java/com/baidu/hugegraph/api/schema/SchemaAPI.java	100.00% <100.00%> (ø)
...n/java/com/baidu/hugegraph/version/ApiVersion.java	75.00% <100.00%> (ø)
...ackend/store/cassandra/CassandraEntryIterator.java	72.46% <0.00%> (-10.15%)	⬇️
.../hugegraph/backend/store/BackendEntryIterator.java	63.38% <0.00%> (-2.82%)	⬇️
...in/java/com/baidu/hugegraph/schema/IndexLabel.java	77.52% <0.00%> (-2.48%)	⬇️
...n/java/com/baidu/hugegraph/config/CoreOptions.java	99.47% <0.00%> (+<0.01%)	⬆️
.../algorithm/records/DoubleWayMultiPathsRecords.java	96.66% <0.00%> (+0.07%)	⬆️
...m/baidu/hugegraph/backend/tx/GraphTransaction.java	79.87% <0.00%> (+0.12%)	⬆️
... and 5 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 634e4f9...c73fea2. Read the comment docs.

[javeme]

update api version