[pgpainless-sop] Add ./pgpainless bash wrapper script

Related to #88.

pgpainless-sop/README.md

@@ -6,16 +6,12 @@ PGPainless-SOP is an implementation of the [Stateless OpenPGP Command Line Inter
 To build an executable, `gradle jar` should be sufficient. The resulting jar file can be found in `pgpainless-sop/build/libs/`.
 
 ## Execute
-You can now use the jar file like described in the stateless OpenPGP cli document.
 
-An example call may look like this:
-```
-java -jar pgpainless-sop-X.X.X.jar generate-key "Alice <alice@wonderland.lit>"
-```
+Simply use the provided `./pgpainless` script to execute PGPainless' Stateless Command Line Interface.
 
 To discover all commands use
 ```
-java -jar pgpainless-sop-X.X.X.jar help
+./pgpainless help
 ```
 
 Enjoy!

pgpainless-sop/pgpainless

@@ -0,0 +1,18 @@
+#!/usr/bin/env bash
+
+# Pretty fancy method to get reliable the absolute path of a shell
+# script, *even if it is sourced*. Credits go to GreenFox on
+# stackoverflow: http://stackoverflow.com/a/12197518/194894
+pushd . > /dev/null
+SCRIPTDIR="${BASH_SOURCE[0]}";
+while([ -h "${SCRIPTDIR}" ]); do
+    cd "`dirname "${SCRIPTDIR}"`"
+    SCRIPTDIR="$(readlink "`basename "${SCRIPTDIR}"`")";
+done
+cd "`dirname "${SCRIPTDIR}"`" > /dev/null
+SCRIPTDIR="`pwd`";
+popd  > /dev/null
+
+BASEDIR="$(cd ${SCRIPTDIR}/.. && pwd)"
+
+exec "${BASEDIR}/gradlew" run --quiet --args="${@}"