Fix Language Injection and Fragment Editor

• Fix NullPointerExceptions when used with IntelliJ Language Injection and Fragment Editor #194

Inspections and JRuby Runtime update

• Support inspections to convert markdown and old style AsciiDoc headings to modern AsciiDoc headings #185
• JRuby runtime updated to 9.1.8.0 to work with recent JDK versions (still, internal Jetbrains JRE is the only supported version) #187

Icons, Search Everywhere, and AsciiDoctor 1.5.6.1

• Support Icon fonts (thanks to @matthiasbalke) / #182
• Update to asciidoctorj-1.5.6 (aka asciidoctor-1.5.6.1) and asciidoctorj-diagram-1.5.4.1
• Support "search everywhere" (double Shift) and "goto by name - Symbol..." (Ctrl+Shift+Alt+N) for all AsciiDoc section headings - just enter a part of the heading
• Support Markdown style sections (starting with '#') in syntax highlighting

Improved Readability for Darcula Theme Headings in Preview

• Headings in Darcula theme preview are now light grey for better readability

Improved parsing for non-printable characters

• Improved handling for non-printable characters in syntax highlighting

Update Asciidoctor to 1.5.5, fixing Bugs

• Update to asciidoctor 1.5.5/asciidoctor-diagram 1.5.4
• Capture Asciidoctor messages on stdout/stderr and write them to IDE notifications
• Close files when images are shown in preview
• Set focus in editor when re-opening file
• Fix "line must be non negative" error when clicking on preview

Support Java 8u111, improved formatting actions

• Make click-on-link-to-open and click-on-preview-to-set-cursor in JavaFX preview compatible with Java 8u111+
• Formatting actions from the toolbar should not throw exceptions when triggered at the beginning or end of the document

Gradle Build and temporary file handling

• Plugin is now build using the Gradle and gradle-intellij-plugin
  This should make contributing and releasing easier. Thanks Jiawen Geng!
• Asciidoctor's temporary files are now created in a temporary folder per opened document. Thanks @agorges!

Fixed code/preview sync for nested HTML (i.e. NOTE)

• Improved handling of trailing spaces in syntax highlighting.
• Fixed code/preview sync for nested HTML (i.e. NOTE)

Updated block parsing

Updated block parsing to support two styles of headings.
Block starts and ends are needed to be aligned in length and shape when parsed.

(see #146)