Fix JSON serialize issues.

[lijunle]

• Handle TypeError JSON serialization.
• Handle parser issue in babel special.
• Integrate self depcheck with JSON output to CI.

[codecov-io]

Current coverage is 98.93%

Merging #69 into master will decrease coverage by -0.34% as of 09b4419

@@            master     #69   diff @@
======================================
  Files           11      11       
  Stmts          274     282     +8
  Branches         0       0       
  Methods          0       0       
======================================
+ Hit            272     279     +7
  Partial          0       0       
- Missed           2       3     +1

Review entire Coverage Diff as of 09b4419

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