added a new application `broot` to solve f(x)=C
fixed a small typo
Merge pull request #7 from yomichi/broot

added a new application `broot` to solve f(x)=C
Fix a bug of output in the case of format 1.
Update README.md
Merge pull request #8 from KenjiHarada/fix-format1-output

Fix a bug of output in the case of format 1.