Hackathon tasks - 3

[nponeccop]

• Use st ^. https://github.com/ptol/oczor/blob/master/src/Oczor/Compiler/Compiler.hs#L100
• Use patterns: https://github.com/ptol/oczor/blob/master/src/Oczor/Converter/CodeGenAst.hs#L52
• Use . and <$>: https://github.com/ptol/oczor/blob/master/src/Oczor/Converter/Converter.hs#L33
• Use $: https://github.com/ptol/oczor/blob/master/src/Oczor/Converter/Converter.hs#L44
• Replace with case: https://github.com/ptol/oczor/blob/master/src/Oczor/Converter/Converter.hs#L108
• Inline instances: https://github.com/ptol/oczor/blob/master/src/Oczor/Converter/Converter.hs#L112
• Change arguments order to eta-reduce: https://github.com/ptol/oczor/blob/master/src/Oczor/Converter/Converter.hs#L130
• Use >>=: https://github.com/ptol/oczor/blob/master/src/Oczor/Converter/Converter.hs#L177
• Use case and move return out: https://github.com/ptol/oczor/blob/master/src/Oczor/Converter/Converter.hs#L407
• Use liftA2: https://github.com/ptol/oczor/blob/master/src/Oczor/Infer/Infer.hs#L18