Jar launcher: Easier scripts maintenance by mutualization

Launch scripts changes for easier maintenance
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- New "jar_launcher" (.sh & .bat) for common configuration (used to be duplicated from one script to another)
- Re-written simplified scripts using jar_launcher

Why ?
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Sharing a common root script allows easier bugfix propagation, as well as focusing on the essential for every different tool (concerned Launcher class, additional possible src-path...).

Compatibility
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Scripts tested on Linux, MinGW & Cygwin.

Possible issue ?
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We now set the "runtime" source-path entry as the **last** one after the user-provided arguments ($@ in .sh / %PARAMS% in .bat) instad of being **first**.
This allows replacing the "runtime" files more easily if needed, since user ones will be found earlier in the path, and if any change, you still use the usual one. If this point causes any debate or issue, please let us know !

Examples
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Our other Mind4SE scripts are now also based on jar_launcher :
- Our Mindoc: https://github.com/Mind4SE/mindoc/tree/master/src/assemble/resources
- MindUnit: https://github.com/Mind4SE/mindunit/tree/master/mindunit/src/assemble/resources
- Mind C++ https://github.com/Mind4SE/mind-cpp/tree/master/mindcpp/src/assemble/resources
- Dependency Tools: https://github.com/Mind4SE/dependency-tools/tree/master/src/assemble/resources/bin
- Mind Visual Diff: https://github.com/Mind4SE/mind-visual-diff/tree/master/src/assemble/resources