SciDAVis - Improvements SVN-temp

- Fixed a small bug in MuParserScript rewrite (column functions can't be optimized, because they implicitly depend on i).

- Fixed legend display when creating a new function plot (closes bug #2714731).
- Fixed entries of function curves when creating a new legend.

- fixed simultaneous changing of column name and comment

- fixed restoring of validity from v0.2 projects

- Fixed translation-related crash when trying to make a polynomial fit using the
fit wizard (closes bug #2766504).
- Factored out axis-independent code in Graph3D::updateScale(), fixing vanishing
minor tick marks after changing scale settings (bug #2706401).

- Fixed loading of table creation times from 0.2.x projects (bug #2726548).
- Fixed crash when numerical integration uses the maximum number of iterations
(bug #2741082).

- some minor fixes to MuParserScript

- muParserScript rewritten as MuParserScript, with the primary aim of making
multiple evaluation of a formula (as when computing function curves with
many points or doing fits with user-defined functions) more efficient.
For example, loading the v0.2.1 test file from bug #2736453 is around 4-5
times faster now.

Also, the new code is supposed to be better documented, more readable,
adhering to the new coding style as described in the LabPlot Wiki, and
generally more suitable for being ported to the new code base.

- fixed Project::path() ("/" should be the project path, not "/project")
- fixed matrix cell() function

- fixed saving of gzipped projects