added contract preamble

[coveralls]

Pull Request Test Coverage Report for Build 157

• 551 of 575 (95.83%) changed or added relevant lines in 4 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+4.0%) to 93.09%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
parsebody/parsebody.go	257	259	99.23%
dedent/dedent.go	84	87	96.55%
gocontracts/process.go	53	59	89.83%
parsecomment/parsecomment.go	157	170	92.35%
<!--	Total:	551	575	95.83%	-->

Totals
Change from base Build 150:	4.0%
Covered Lines:	741
Relevant Lines:	796

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💛 - Coveralls