Remove all unused extlibs

They will not be used in the future, especially since extlibs aren't and
shouldn't be used anymore.

build/extlib/commons-logging/RELEASE-NOTES.txt

@@ -1,22 +0,0 @@
-              Apache Commons Logging
-                  Version 1.1.3
-                  RELEASE NOTES
-
-The Commons Logging team is pleased to announce the release of Apache Commons Logging 1.1.3
-
-Commons Logging is a thin adapter allowing configurable bridging to other,
-well known logging systems.
-
-This is a maintenance release containing bug fixes.
-
-Changes in this version include:
-
-Fixed Bugs:
-o LOGGING-151:  Use "org.apache.commons.logging" as bundle symbolic name. Thanks to Krzysztof Daniel.
-
-Historical list of changes: http://commons.apache.org/proper/commons-logging/changes-report.html
-
-For complete information on Commons Logging, including instructions on how to submit bug reports,
-patches, or suggestions for improvement, see the Apache Commons Logging website:
-
-http://commons.apache.org/proper/commons-logging/