BVAL-296 Fix misalignment between string and API representation in JavaDoc
BVAL-292 & BVAL-293 Renaming ConfigurationSource to XMLConfiguration

 Clarifying the javadocs:
 - Configuration#getXMLConfiguration never returns null and only applies for validation.xml
BVAL-293 Renaming ConfigurationSource#getConstraintMappingResourcePath() to getConstraintMappingResourcePaths()
BVAL-293 Removing unnecessary public modifier
BVAL-293 Rename XMLConfiguration to BootstrapConfiguration
BVAL-298 Using ServiceLoader to load validation providers

 Adding test and upgrading plugin versions
BVAL-298 The current caching of the ValidationProviders don't work, because the providers themselves keep a hard reference to the class loaders. Wrapping the list of providers into a SoftReference instead (see also ValidationTest)
BVAL-298 Making sure to keep a hard reference to the list of providers when checking the cache in order to prevent garbage collection in the time between the check and returning the list
BVAL-298 Wrapping the whole provider discovery into a PrivilegedAction
BVAL-298 Removing obsolete comment
BVAL-298 Changing error message in case ServiceLoader cannot load a provider
BVAL-298 Changing source and target level for compiler plugin (ServiceLoader is part of Java 6). See also BVAL-299
BVAL-298: Applying renaming of ConfigurationSource on rebase
BVAL-282: Adding note on mark/reset contract to JavaDoc
BVAL-280 Adding test for behavior of multiple proviers w/ at least one unknown (not loadable)
BVAL-230 Switching accepted type String to the more generic CharSequence
BVAL-230 Formatting.
BVAL-259 Enforce that evaluation fails on first error
BVAL-274 Add aggregation methods in metadata API for method interception integrators
BVAL-304 Adding the maven-bundle plugin to generate the bundle information

Removed the <pluginManagement> node and updated all used plugin versions