GSim 0.15.0 released

What's new in this version:

* Multi-windowed mode has been introduced. That required a substantial changes in the code. Some related bugs still possible.

* 'Reload&process' button reloads selected datasets and process them by single shot

* Improvement in integration routine: integral curves for 1D data can be arbitrary shifted/scaled

* Custom print logo in SVG format can be specified

* New 'Smart sideviews' mode for 2D spectra allow to see interactively slices or projections

* The colour and the font of the text and line objects can be altered by user.

* Updated Windows installer

* Based on new Qt 4.3.0

* Several bug fixes.