Compatibility with QGIS 1.8
Misc bugfixes and small improvements

Legend shows quantity (data set)
Trimming of spaces at the end of data set name
Default color ramp available for generation of color maps
Removed button box from vector options dialog

The user does not need to click ok/apply to keep the changes.
This is consistent also with the color map properties dialog.
Render vectors with anti-aliasing and more suitable pen settings.

Also, render vectors after mesh for better visibility of arrows