演算子の名前変更
掛け算の演算子の優先順位変更
a
revert
/-:*の処理修正
Fraction型の定義の簡略化
Fractionの定義の簡略化2
Merge https://github.com/MichaeGon/ExperimentOfHaskell

Conflicts:
	myhaskell.hs
Merge https://github.com/MichaeGon/ExperimentOfHaskell

Conflicts:
	myhaskell.hs
	myhaskell.hs~