Deprecate the dev option

[lijunle]

Resolve #114

• Show deprecation hint if run in CLI. However, not show hint if run by API, we are not pollute the caller's console
• Update the documentation.

[codecov-io]

Current coverage is 96.44%

Merging #120 into master will increase coverage by +0.04% as of 9eae11e

@@            master    #120   diff @@
======================================
  Files           22      22       
  Stmts          417     422     +5
  Branches        80      81     +1
  Methods          0       0       
======================================
+ Hit            402     407     +5
  Partial          8       8       
  Missed           7       7       

Review entire Coverage Diff as of 9eae11e

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