Change tabs to spaces; elim trailing whitespace.

Change tabs to spaces; elim trailing whitespace.

To comply with Sonar style requirements, replace all tab characters
with four whitespace characters/spaces, and remove all trailing
whitespace. Perform this change to all Java and XML files.

Also replace tabs with "\t" in test strings that require tabs,
and edit STPIndenterTest so that it doesn't rely on indented comments.

Change-Id: I48c3c5449a58fe5310967d998a05df1a28fbcbb0
Signed-off-by: Andrew Ferrazzutti <aferrazz@redhat.com>
Reviewed-on: https://git.eclipse.org/r/25561
Reviewed-by: Alexander Kurtakov <akurtako@redhat.com>
Tested-by: Alexander Kurtakov <akurtako@redhat.com>