DirSupport move simplification

The "fallback" was needed only in one case, when
a dir was moved to it's subdir. But, to achieve
that one must declare excludeFilter. Hence,
from now on, WITHOUT filter that is impossible,
and in the same time, other IOEx from Files.move
should not be swallowed (ie. move over non-empty dir)
Split the method in two: move and pseudoMove
extract the merge of specs-index files into own class to allow
to process one stream after the other.
extract the manipulation of specs index files into its own class.
it is meant as create one when you need it and then throw it away.
this also means RubygemsGateway is now a little more then a factory
of ruby objects which have a java interface and has no more mutable
state.
fix api change after rebase
Merge remote-tracking branch 'origin/nexus-2.11.x' into nexus-2.11.x-dirsupport-move-simplification
Rename method
Merge pull request #772 from sonatype/nexus-2.11.x-dirsupport-move-simplification

[2.11.x] DirSupport.move simplification
Verious cleanups:

NEXUS-7508: logging
NEXUS-7512: silly code
and other (removal of deprecated code, duplicated code...)
Removal of newScript method
Made log WARN and added stack trace
Merge pull request #780 from sonatype/nexus-2.11.x-ruby-cleanup

[Ruby] Various cleanup
Merge pull request #779 from mkristian/remove-state-in-DefaultRubygemsGateway

Remove state in default rubygems gateway
* reduce RubygemsGateway to a factory of ruby classes
* refactored repository repair methods into own helper class
* follow the same code pattern of ruby clases for DependencyDataImpl