Do not attempt to publish if no artifacts are present

Ivy transactional publishing will abort if no artifacts
are published, either because the temporary directory is
not being created, or because Ivy will detect an anomalous
condition.

Therefore, skip publishing altogether if there is
nothing to publish to begin with.
Merge pull request #1300 from cunei/wip-fix-ivy-move

Do not attempt to publish if no artifacts are present
DerivedSetting not a DefaultSetting anymore
Derived settings to replace their DerivedSetting, not go at the beginning
Derive settings only under the scope of the DerivedSetting
Decouple DefaultSetting from Setting/DerivedSetting; BuildCommon.derive() produces default settings by default
Put sbt's derived settings under GlobalScope
Optimise scope intersection for GlobalScope
Couple of fixes
Improve SettingsExample to allow orthogonal scopes (like projects/tasks) at a certain nestIndex
Add 2 derived settings tests:

1) non-default derived settings, if they produce anything, the settings
   they produce must supersede previous assignents (in the settings seq)
   to the same key.

2) even if a derived setting is scoped at a higher scope (e.g.
   ThisBuild) the settings it produces are scoped at the intersection of
   that (the defining) scope and the scope of the triggering dependency.

2 is particularly nice as it enables this behaviour:
    derive(b in ThisBuild := a.value + 1)
    a in project1 := 0
    // a could be defined in all projects
    ==>
    Now (b in project1).value == (a in project1).value + 1 == 1
    and similarly in all other projects
    all with a single derived setting
Fix native package location for bintray distribution.
Fix for new location of MSI files.
removing last type in python conf.
added npt as new Utility Plugin
Added links to `imagej` and `install4j` plugins
Merge pull request #1303 from sbt/wip/merge-0.13.2

Merge 0.13.2
Merge pull request #1036 from dansanduleac/derivedSettings

Allow derived settings to replace previously-defined but non-default settings
sbt 0.13.2
added scalariform