automatically add imports for core objects and plugins in ui console

[dumoulin]

For instance, we have to add a lot of imports when defining a mole in a script for ui console.

• Common objects of the core could be automatically imported, at least the most importants/used.
• tasks available as plugin could also be automatically imported with a collision detection mechanism. Thus, if two classes with same name are found, imports are not added and a warning is displayed when the console is started or a plugin is loaded.

[dumoulin]

An other solution than adding import is to provide a builder that provides convenient methods for building common objects. An example session can be:

t1 = builder.buildGroovyTask()
t1.setCode("println 't1'")
t2 = builder.buildGroovyTask()
t2.setCode("println 't2'")
builder.buildMole(t1, t2).run()

[dumoulin]

implemented in r3459, see DevDoc/UIConsole.