Enabled three ignored execute via post tests
Throw exeption when output can not be stored

If we do not do this, in case something goes wrong while storing the
output we get a response document that says process succeeded but has an
empty result.
Removed some warnings
Fixed a bug in ExecuteResponsbuilder, added tests

This should fix the bug Matthias Hinz has described about wrong mime
types beeing assigned to output data.
Use smaller tif for binary tests, renamed tests

Now a 3 KB large tif file is used instead of the old 800 KB large one.
Also, some asynchronous test were named synchronous. I changed this.
Removed old XmlSchema 1.1 dependency

XmlSchema 1.4.2 is used instead.
Adjusted waiting time for asynch execute tests

As the tiff files for binary execute tests are now much smaller, I
halved the waiting time for asynch execute tests.
Merge remote-tracking branch 'upstream/master'
Merge branch 'executeresponsebuilder-bug'
Merge branch 'allexecuteposttests'
Removed duplicate method
Re-adjusted link to GPL 2.
Refactored GeoServer output generators
Merge pull request #17 from bpross-52n/master

Fixed a bug in ExecuteResponseBuilder, added more tests, cleaned up. 
There seems to be no discussion.
adjust poms: remove log4j, add slf4j+logback
add logback.xml, remove log4j.properties
adjust logger syntax to slf4j
Merge pull request #19 from matthesrieke/master

Migrate to SLF4J+Logback [v2]
Merge remote-tracking branch 'upstream/master'
Adjusted to slf4j