Declare result types for analyzers.

[hxtk]

This change declares each of the analyzers in the analyzers package to have a result type of []github.com/praetorian-inc/gokart/util.Finding.

A test has also been included that runs a minimal *analysis.Pass through each analyzer's Run function, reflectively determines the type of the result value, and compares it to the declared result type of the analyzer.

Resolves #76.