Fix bug where ginkgolinter fails other linters

[nunnatsa]

ginkgolinter no longer write to the ast tree, and should not fails other linters anymore. Instead, it computes the suggested fixes using a clone, from the github.com/go-toolsmith/astcopy package

Fixes #39

[coveralls]

Pull Request Test Coverage Report for Build 4082162120

• 1 of 1 (100.0%) changed or added relevant line in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.02%) to 87.889%

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Totals
Change from base Build 3946232596:	0.02%
Covered Lines:	537
Relevant Lines:	611

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💛 - Coveralls