Added `executable` exec mode

Use the executable exec mode to leverage locally installed plantuml binaries, eg via homebrew

Fixed interactive `plantuml-set-exec-mode`

Make sure plantuml-set-exec-mode can be actually invoked interactively, see #97

Easier first setup with `plantuml-download-jar`

New features

• #95 The setup for new users is made easier by downloading the latest release of PlantUML straight into the right place (plantuml-jar-path) by invoking plantuml-download-jar

Avoid messing with window layouts and buffers

Fixes #66

Revamped indentation support

New indentation system, now with a proper test coverage

Fix indentation issues

Merged #85 to fix indentation issues and #82 to actually enable altering plantuml-java-args

Relicensing to GPLv3+

As part of the MELPA-wide efforts to align licenses of packages to be compatible with Emacs, plantum-mode is now licensed under GPLv3 and later versions.

Functionally, this release is identical to v1.2.3.

Unicode support

#50 Added support for unicode in output files

Bugfix: better handling of java commands

#40 In some cases, properly running the java command needed to execute PlantUML was not working (e.g. due to spaces in the path).

Bugfix: support for `~` path expansion

#43 Added support for paths such as ~/plantuml.jar, where the ~ was previously breaking