Upgrade to Gradle 1.8 and propdeps 0.0.5
Polish build.gradle
Remove superfluous spaces in asciidoc

Remove the superfluous spaces that appear in the asciidoc source.

Issue: SPR-11096
Add whitespace to improve asciidoc readability

Issue: SPR-11096
Restore multi-page and PDF reference documentation

Generate docbook xml from the asciidoc reference guide and use the
docbook-reference-plugin to generate HTML (single and multi-page) and
PDF documentation.

Issue: SPR-11096