Add a class in orbisgis core to convert a layer into image stream
Export map editor tool in Orbisgis view
Add DPI input
Add icon and fix layout issues.

I redid the InputPanel class's layout using MigLayout. I also removed
the grouping since it wasn't used anywhere and made the code rather
complicated to read.
Add confirmation for overwrite
Do some translations
Adds package info in the maven projects.
Note that it only concerns the top-level package of each project. See
issue #517
related to #523.
 We were not able to open the simple editor after having saved a unique
symbol area with no stroke. Indeed, the fillLegendMemory attached to
LinePanel was a NullPenStrokeLegend so the init method threw a
IllegalStateException...

The fix is not that clean. We have code where constructors have coupling
with listeners and that produce border effects. I've decided to go as
fast as I could as this design has already been discussed and accepted.
It may change later, however, in order to separate behaviour management
from initialization.

I rely here on a new field that lets me know if the stroke (or fill,
resp.) was originally set so that I can decide if fields must be enabled
or not. It seems to be working, bu I may have missed something, so please
test it.
Fix a problem in PnlProportionalPointSE.
When disabling the stroke of the proportional point, some bad values
were set in the associated Symbolizer. More accurately, we obtained a
Stroke with a null color and that led to a NPE.

I make deeper tests here so that we use the expected objects in both the
legend and the symbolizer. Seems to work, but needs to be tested.
Fix management of mapped legends when the stroke is disabled.
We're now able to deal with it so that, when editing single
configurations or the fallback configurations, the fields associated to
the line configuration are disabled. I've managed to do this by checking
if the stroke is enabled or not in the parent legend. If it is disabled,
I replace the PenStrokeLegend in the temporary unique symbol with a
NullPenStrokeLegend.
improves javadoc and adds a default description in new Rules
Adds Description management in the PnlRule.
Description are made of a title and/or abstract associated to a Locale.
We now have a ComboBox managing the locale and updating text area fields
that can be used to change the abstract and title.
Improves the content of the combo box.
It is now a WideComboBox that relies on ContainerItem instances.
The abstract text area is now in a JScrollPane.
We now remove titles and abstracts that are empty or null.
Adds description in Style and description management in PnlStyle
adds french translation for the keys I added
Merge pull request #519 from nicolas-f/feature/export-mapeditor

MapEditor export image tool

* Create MapImageWriter, taken from WMS server in order to easily convert a layer into an image stream.
* Add a new tool in MapEditor to export the current rendered map into an external PNG or TIFF file.
adds translations
Merge remote-tracking branch 'upstream/master' into 486-merge

Conflicts:
	orbisgis-view/src/main/resources/org/orbisgis/view/translation/language/fr.po