Fix a few more spellos.
Fix help text for Catalog search.
Fix additional typo identified by Phil Klinefelter

See https://github.com/codice/ddf/pull/15#commitcomment-3640160
DDF-98: Fixes to SourcePoller / SourcePollerRunnable to status sources in a thread
DDF-98: fixed formatting and added locks in the SourcePollerRunnable to prevent multiple status threads running concurrently on the same source
DDF-99: Updated spring repo references to point to the correct URLs.
DDF-100: threaded addingSource() so that its time consuming startup does not blacklist
it on slow Source's initialization, e.g., bad Sources
DDF-98: incorporated code review comments
Merge pull request #23 from jlcsmith/master

DDF-98: Merge SourcePoller fixes to improve performance with unresponsive sources.
DDF-84: Features now copy to correct area in system.

Also updated features file to pull in the maven repo automatically instead of having it hardcoded.
Increasing log threshold to hide unneeded test logging that is causing travis-ci build to fail.
DDF-79: merged with latest master
DDF-78: Submitted on behalf of a third-party: Brad Hards. Merge branch 'master' of http://github.com/codice/ddf into bradh-master
DDF-78: fixed merge of wrong parent version
DDF-99: re-added karaf 2.3.2 upgrade changes after bad merge
DDF-97: Raised log threshold.

Large number of logs were causing build errors on travis preventing testing of WSS configurations.
DDF-102: Adding checking of content-disposition.

Added check for filename in HTTP header and also converted code to use SLF4J.
DDF-94 null check for metadata field of metacards.
DDF-94 Added unit tests for how predicates handle null contextual data.  Added null checks into Contextual and Entry Predicates.
DDF-94 removed other potential NPE identified in code review.