Merge branch 'hotfix/1.7.3'
Update stentry keycol process for flagging #1464
Change getString to use param #1460
Refactor Content object usage #1455

Remove the use of Content object in favor of passing object directly.
Correct Java license boilerplate
Support external images in PDF image #1468
Process common attributes in chhead in XHTML #1469
Remove IBM bookmap demo abstract from PDF #1455
Clean logging #1471

To make transition to other logging frameworks easier, reactor logging:

* Remove support for Properties as message arguments
* Replace logException with logError
* Remove logFatal and logException
Troff transform producing invalid output #1473
Fix logging Ant task bugs

The bug was introduced in 040aa1804395c91fb6b016ca1f8873355f2bfbea.
Add out.ext support to troff

Use out.ext property to define troff output file extension.

Add troff.outformat property to define OUTFORMAT XSLT parameter.
Fix PDF colwith percentage unit bug #1477
Correct path in error message #1475
Fix msgblock output in PDF #1472
Fix index entry bug in PDF using XEP #1423
Merge branch 'develop' into python
Update Scala code based on source Ant changes
Fix topic wide index range in PDF #1080

Split opentopic-index:index.entry processing in topic content into
multiple templates. This removes simple index entries for ranges, but
they are not needed.
Add support for index ranges in map #1080