NX-392: Completely remove old plugin manager and related classes
NX-392: improve startup performance (GLOBAL_INDEX maps to getResources which is faster than findEntries for bundles with embedded jars; when we move to fine-grained bundles we can go back to INDEX)
NX-392: cleanup logging
NX-392: use ApplicationDirectories to access ${nexus-app} path
Add nexus-app property to legacy IT client
Merge pull request #498 from sonatype/NX-392-remove-plugin-manager

NX-392: Completely remove old plugin manager and related classes
Merge branch 'master' into extract-webresources-api

Conflicts:
	components/nexus-core/src/main/java/org/sonatype/nexus/guice/StaticWebResourceBundle.java
	plugins/basic/nexus-plugin-console-plugin/src/main/java/org/sonatype/nexus/plugins/plugin/console/DefaultPluginConsoleManager.java