Improve rendering of nested lists

[msimacek]

Adds additional indentation to support nesting of lists. Uses a stack to
keep track of numbering for ordered lists.

Fixes #18

[cpuguy83]

Thanks, can you provide a sample output? A test would be nice, but I know this project is severely lacking in that area.

[cpuguy83]

oh wow, I can't believe this global is even here... should be moved to the renderer object

[msimacek]

Sample input (excerpt from docker-cp manpage):

Assuming a path separator of `/`, a first argument of `SRC_PATH` and second
argument of `DEST_PATH`, the behavior is as follows:

- `SRC_PATH` specifies a file
    - `DEST_PATH` does not exist
        - the file is saved to a file created at `DEST_PATH`
    - `DEST_PATH` does not exist and ends with `/`
        - Error condition: the destination directory must exist.
    - `DEST_PATH` exists and is a file
        - the destination is overwritten with the source file's contents
    - `DEST_PATH` exists and is a directory
        - the file is copied into this directory using the basename from
          `SRC_PATH`
- `SRC_PATH` specifies a directory
    - `DEST_PATH` does not exist
        - `DEST_PATH` is created as a directory and the *contents* of the source
           directory are copied into this directory

Output:

.PP
Assuming a path separator of \fB\fC/\fR, a first argument of \fB\fCSRC\_PATH\fR and second
argument of \fB\fCDEST\_PATH\fR, the behavior is as follows:

.RS
.IP \(bu 2
\fB\fCSRC\_PATH\fR specifies a file

.RS
.IP \(bu 2
\fB\fCDEST\_PATH\fR does not exist

.RS
.IP \(bu 2
the file is saved to a file created at \fB\fCDEST\_PATH\fR

.RE
.IP \(bu 2
\fB\fCDEST\_PATH\fR does not exist and ends with \fB\fC/\fR

.RS
.IP \(bu 2
Error condition: the destination directory must exist.

.RE
.IP \(bu 2
\fB\fCDEST\_PATH\fR exists and is a file

.RS
.IP \(bu 2
the destination is overwritten with the source file's contents

.RE
.IP \(bu 2
\fB\fCDEST\_PATH\fR exists and is a directory

.RS
.IP \(bu 2
the file is copied into this directory using the basename from
\fB\fCSRC\_PATH\fR

.RE

.RE
.IP \(bu 2
\fB\fCSRC\_PATH\fR specifies a directory

.RS
.IP \(bu 2
\fB\fCDEST\_PATH\fR does not exist

.RS
.IP \(bu 2
\fB\fCDEST\_PATH\fR is created as a directory and the \fIcontents\fP of the source
directory are copied into this directory

Output rendered:

       Assuming a path separator of /, a first argument of SRC_PATH and second
       argument of DEST_PATH, the behavior is as follows:

              · SRC_PATH specifies a file

                · DEST_PATH does not exist

                  · the file is saved to a file created at DEST_PATH

                · DEST_PATH does not exist and ends with /

                  · Error condition: the destination directory must exist.

                · DEST_PATH exists and is a file

                  · the destination is overwritten with the source file's contents

                · DEST_PATH exists and is a directory

                  · the file is copied into this directory using the basename from
                    SRC_PATH

              · SRC_PATH specifies a directory

                · DEST_PATH does not exist

                  · DEST_PATH is created as a directory and the contents of the
                    source directory are copied into this directory

Ouput without this PR for comparison:

       Assuming a path separator of /, a first argument of SRC_PATH and second
       argument of DEST_PATH, the behavior is as follows:

       · SRC_PATH specifies a file

       · DEST_PATH does not exist

       · the file is saved to a file created at DEST_PATH

       · DEST_PATH does not exist and ends with /

       · Error condition: the destination directory must exist.

       · DEST_PATH exists and is a file

       · the destination is overwritten with the source file's contents

       · DEST_PATH exists and is a directory

       · the file is copied into this directory using the basename from SRC_PATH

       · SRC_PATH specifies a directory

       · DEST_PATH does not exist

       · DEST_PATH is created as a directory and the contents of the source directory
         are copied into this directory

[cpuguy83]

LGTM

thanks!