Make maven-bundle-plugin (felix) managed and merge executions (*)

Version property was a unsatisfying solution for same version in every
pom, also this alowes for shared settings.

(*) actual merge was of plugin tags. There is now only one left which
contains two execution tags.

Also, plugin version was updated.
Do not override managed version of maven-bundle-plugin

Is now managed by parent pom since last commit. Also, the tag
<extensions>true</extensions> was added to avoid duplicate execution
tag in poms. This tag tells the plugin that settings (provided in parent)
for the already defined execution are extended by this plugin tag.
Export referenced packages and fix typo

Not exporting the dependent packages (org.bushe.swing.event.*) produces
warnings in maven compilation.
Export all io.scif subpackages and do not embed bundles

Removed obsolete imglib2-meta dependency exclusion and unnecessary
repository definition.
Fix imglib2 pom not compiling

net.imglib2:imglib2-algorithms-gpl, mpicbg, net.imagej:ij was removed from
dependencies.
osgi does not allow importing classes from default package or including
them in a bundle. Maven will simply not compile with classes in the default
package, since the felix plugin fails.

Dependency tree:
> net.imglib2:imglib2-algorithms-gpl (removed)
	> mpicbg
		> net.imagej:ij (source of error)

Full error message from maven (happens during execution of
maven-bundle-plugin):

[ERROR] Bundle org.knime.knip:org.knime.knip.imglib2:bundle:2.1.0 :
The default package '.' is not permitted by the Import-Package syntax.
 This can be caused by compile errors in Eclipse because Eclipse creates
valid class files regardless of compile errors.
The following package(s) import from the default package null
Manage version of maven-bundle-plugin

Version is now managed by parent pom. This commit also fixes packages
referenced by exported packages not being exported and formats the
<Require-Bundle> tag to be more overseeable.