Update docs for 2.6.0 to reflect what's been added/changed

[jonbullock]

Update docs for 2.6.0 to reflect what's been added/changed:

• Support added for index page under /tags (Add rendering support to generate /tags homepage and tag model jbake#371) @manikmagar Fixed with Updated docs for jbake-org/jbake#371 #83
• Switch to flexmark from pegdown - do extensions need updating?? (replace pegdown with felxmark-java jbake#376) @jonbullock
• Include details of JBake environment variable support (Improve i18n support of Jbake script jbake#182) @jonbullock
• Support for ignoring folders from being processed (Allow certain folders to be ignored from being processed either as content or assets jbake#324) @manikmagar Fixed with Update docs for jbake-org/jbake#390 #81
• Support for image existing in content folder (Allow folders to be ignored and have static files in content folder jbake#390) @manikmagar Fixed with Update docs for jbake-org/jbake#390 #81
• Support for extra JAR's being added to classpath (Improve exec scripts to pick up all jar files in /lib jbake#230) @jonbullock
• Added AsciiDoctorJ-diagram (pickup jars in distribution lib directory and add asciidoctorj-diagram as a distribution dependency jbake#385) @jonbullock
• Extended watch mode to template & asset folders (Extended JBake watch mode to template and asset folder jbake#384) @manikmagar Fixed with Update docs for jbake-org/jbake#384 #82
• Automatic update of img src content (Prevent image source path from breaking jbake#367) @manikmagar Fixed with Updated doc for Jbake-org/jbake#367 #85
• Added nextContent/previousContent variables (Add document navigator data model jbake#364) - Fixed with Updated 2.6.0 docs for Document navigator variables #80
• Update to Java 7 (Consider moving to Java 7 jbake#107) @jonbullock
• -s option will override site.host variable (jbake -s should automatically override site.host jbake#333) @jonbullock
• Default doc type support (Support for default document type specified in configuration file. jbake#278) @jonbullock
• Absolute path support (Support absolute paths for asset, content and template folders jbake#229) @jonbullock

[benelog]

Thank you for your documentation.
I am eagerly awaiting the 2.6.0.