Add developing notes, building the package etc.

DEVELOPING.md

+Building the NoiSee package
+===========================
+
+The package is based on the [example-script-collection][gh_example-script] which
+is using [Maven][www_mvn] as the build system. To build the package, simply run
+`mvn` on the command line or launch the helper script that optionally takes the
+path to your *Fiji* location as a parameter, using it to tell maven where to
+deploy the resulting package (defaulting to `/opt/Fiji.app/`):
+
+```
+bash scripts/build_and_deploy.sh </path/to/your/Fiji.app/>
+```
+
+Making a new release
+====================
+
+To create a new release, clone the [scijava-scripts][gh_scijava-scripts] repo
+(e.g. in `/opt/imagej/`) and run the `release-version.sh` helper:
+
+```
+BASE_DIR=/opt/imagej
+mkdir -pv "$BASE_DIR"
+cd "$BASE_DIR"
+git clone https://github.com/scijava/scijava-scripts
+cd -
+
+"$BASE_DIR/scijava-scripts/release-version.sh" --skip-push --skip-gpg
+```
+
+[gh_example-script]: https://github.com/imagej/example-script-collection
+[www_mvn]: https://maven.apache.org
+[gh_scijava-scripts]: https://github.com/scijava/scijava-scripts