output: fix warning for storage

Som arguments were not used in implementation.
Parameters 'columns' and 'rows' of plugin are used only if they are
both non zero values.
decision: fix warnings
petrinet: fix warnings

- a boolean ok was set but not used
- a break instruction was missing into a case statement
exs: fix warnings

a Matrix was set but not used in testfsa
muparser: fix the CMakeLists for Cpack and version

- A VLE_NAME project was missing for using CPack
- Version of ext.muparser is set to 0.1.0 as others
forrester: fix CMakeLists

- define VLE_NAME for CPack
- takes into account option WITH_DOC
- search for gvle rather than all dependencies
Merge pull request #14 from rtrepos/pullrequest

Fix warnings and CMakeLists of packages