forrester: update terminology

Little changes have been made to the terms used for the GUI.
(closes #17)
packagevle-1.1.0-beta1
all: update CMakeLists.txt without GVLE

The decision, difference-equation, fsa and petrinet must be use without the
graphical user interface ie. GVLE and its dependencies. (closes #38).

- We fix the variable HAVE_GVLE for all package.

- We update the FindVLE and FindGVLE from VLE repository.
cmake: update FindVLE and FindGVLE

- related to commit 550d21096be9c8a0d965b3617a11a707c697be03 of vle
- related to commit 2bc632b82032f9caa78cd66a30dc740e81de3f30 of vle
- related to commit d1a8cfd63cc6610a1d447300f2ef2f949f921909 of vle
- related to commit 39f3bdca3e7cf944494b6f8dc939c69f7f9c6903 of vle
forrester: update the observables generator

Observables are not removed each time a model is regenerated.  If the
observable exist it is keeped, and if a observable is not any more
needed it is removed.
(closes #36)
forrester: update the Conditions

The variables initialisation system has been updated. Atomic double
port parameter are used in order to ease analyses with R. Each
Variables will have a port parameter with its name and its initiial
value.
(closes #44)
forrester: fix the drawing area refreshment

The pixmap needed to be resized at the wright time, followed by a
queueRedraw.
(closes #46)
differential: set a default initialisation

An initialization is required for all states variables.
Otherwise an exception is thrown. We modify this behavior
by setting a default initilialization value to 0 for variables
that are not explicitely initialized. (Closes #42)
differential: allow the update of state variables

- add an operator= for Var which updates the state value
- add a constructor that initializes the value
- add a const access operator to the state value (for observation)
differential: simplify the initialisation

Variables can now be initialised using the InitEventList as the container of
initialisedvalues. The vpz Ladybirdplantlouse is modified for testing
purpose (Closes #41).
all: fix CPack directives

The binaries are now built into "buildvle" directory. This directory is
now ignored when packaging.
muParser: fix the name of the CMake project

The name of the project now matches the name of the pkg.
decision: fix the data directory management

A new port parameter is generated by the modeling plugin. the
PackageName parameter tell where to load the plan file.
(closes #51)
package-1.1.0-beta2
ChangeLog: removed

We remove ChangeLog from repository.
README: switch to rst
README: add ext.muparser and vle.forrester

The repository have now ext.muparser and vle.forrester packages.
README: update
decision: fix the plugin selection management

The member data structure of the drawing area dedicated to the
selection where not reset when the modeling plugin were reuse inisde a
gvle session.
(closes #55)
decision: fix the plugin model settings

When finished to edit a model with the modeling plugin, the generated
dynamic, and the generated experimental conditions are set to the
model.
(closes #56)