Math: Add lcm and gcd
Merge pull request #208 from aomoriringo/master

Math: Add lcm and gcd
Math: Fix gcd about 0
Math: doc: add empty line
Math: doc: fix typo
Merge pull request #209 from aomoriringo/master

Math: Fix gcd about 0
Text.Table: Support powerful width feature.
Text.Table: Support powerful joint/border feature.
Text.Table: Add tests.
Text.Table: Update document.