Solve issue #492.
The nullity check is not enough anymore since we've tried to avoid null
values in PenStroke fields. We must check that the dashArray is not
empty before trying to find double values in it. If we do not, we'll
obtain an NumberFormatException.
Fix a problem with the apply button in the advanced editor.
It replaced the list of available styles, in the TOC, with a new list
containing only the style being edited currently.
Merge pull request #493 from agueganno/bug-hatches

    * Draw a HatchedFill on a polygon layer with an empty dash array (previously impossible)
    * Don't delete all styles except the one being edited when clicking Apply in the Advanced Style Editor.
Modify constructors for Unique/Proportional
Modify constructors for classifications

Note that with these new constructors, for Interval Classifications, the
interface is constructed correctly, but I have a ParseException in the
CanvasSE class (even though I haven't touched CanvasSE). Beginning of
the stacktrace:

    ERROR gui.class org.orbisgis.view.toc.actions.cui.components.CanvasSE  -
    org.gdms.sql.engine.ParseException: Parse error on line 1 at character 42:
        found ',', expected ';'.
	at org.gdms.sql.engine.step.parsing.ParsingStep$.doOperation(
        ParsingStep.scala:64)
Oops, forgot to select the first item.
Small cleanup
Create new ui package
Create new components package
Simplifies and add javadoc on goToNode
Creates a GoToNodeButton class that can be used for single properties
too.
Add proportional spinners

Fixes #503. See also #443.
Oops, I wasn't setting UOMs correctly

Note: This doesn't work with localized strings for now
Make sure max is always >= min.
Remove unused class
Fix a localization problem for WKN
Improve the Util class
Updata javadoc for components package

Left to do:

    * Update javadoc for panels package
    * Fix UniqueSymbolPanel constructor / inheritance
    * Reorganize inheritance in the ui package
    * Make a Preview panel

Later:

    * Extract classification panel elements
    * Extract classification computation methods into a computation
      package
    * Add a lock for symbol width / symbol height and maintain the
      aspect ratio
    * Add a preview for the minimum size in proportional legends
Clean up unique symbol/proportional panels
Add missing methods to IInterpolationLegend