tree f13bde4d16d2538fe0467d4c00ec9eef50ce9244
parent c2d3fbe0937b8ffea8de1953066ca23df1e98238
author Won Wook SONG <wonook@apache.org> 1552977404 +0900
committer John Yang <johnyangk@gmail.com> 1552977404 +0900

[NEMO-358] Recycling vertex ids while cloning a vertex  (#201)

JIRA: [NEMO-358: Recycling vertex ids while cloning a vertex](https://issues.apache.org/jira/projects/NEMO/issues/NEMO-358)

**Major changes:**
- Implementation on the IDManager so that it saves the IDs that are no longer used, to be reused later on.
- Fixes the LoopExtractionPass (where cloning occurs) to meet with the new implementations.

**Minor changes to note:**
- None

**Tests for the changes:**
- Existing tests confirm the changes.

**Other comments:**
- None

Closes #201