Two new options: --keep-blank-lines and --disable-indent-subroutine

[zaikunzhang]

First of all, thank you very much for developing this great package.

In the current version, fprettify removes the consecutive and trailing blank lines. However, some programmers may like to keep those lines. Therefore, it might be a good idea to introduce a new option for such a possibility. This is what "--keep-blank-lines" for.

The idea of "--disable-indent-subroutine" is similar to that of "--disable-indent-mod". It disables the indentation for the body of a subroutine or a function.

Thank you for your consideration, and again, for this very useful software.