Support Jira 7.7.X

@Rpaasche, @vrenjith -- it looks like the build process is failing (see below). I'd prefer to download the plugin directly from the marketplace. Any chance someone could fix the build process and push the 7.8 release up to the marketplace?

Downloading: https://repo.maven.apache.org/maven2/com/atlassian/jira/jira-plugins/7.8.0/jira-plugins-7.8.0.pom
[ERROR] The build could not read 1 project -> [Help 1]
[ERROR]   
[ERROR]   The project info.renjithv.jira.addons.threadedcomments:threaded-comments:1.20-SNAPSHOT (/home/ubuntu/jira-threaded-comments/pom.xml) has 9 errors
[ERROR]     Unresolveable build extension: Plugin com.atlassian.maven.plugins:maven-jira-plugin:6.3.7 or one of its dependencies could not be resolved: Could not find artifact com.atlassian.maven.plugins:maven-jira-plugin:jar:6.3.7 in central (https://repo.maven.apache.org/maven2) -> [Help 2]
[ERROR]     Unknown packaging: atlassian-plugin @ line 14, column 16
[ERROR]     Non-resolvable import POM: Could not find artifact com.atlassian.jira:jira-plugins:pom:7.8.0 in central (https://repo.maven.apache.org/maven2) @ line 28, column 25 -> [Help 3]
[ERROR]     'dependencies.dependency.version' for javax.ws.rs:jsr311-api:jar is missing. @ line 74, column 21
[ERROR]     'dependencies.dependency.version' for com.google.code.gson:gson:jar is missing. @ line 79, column 21
[ERROR]     'dependencies.dependency.version' for javax.xml.bind:jaxb-api:jar is missing. @ line 99, column 21
[ERROR]     'dependencies.dependency.version' for com.atlassian.plugins.rest:atlassian-rest-common:jar is missing. @ line 104, column 21
[ERROR]     'dependencies.dependency.version' for com.atlassian.sal:sal-api:jar is missing. @ line 109, column 21
[ERROR]     'dependencies.dependency.version' for com.atlassian.activeobjects:activeobjects-plugin:jar is missing. @ line 132, column 21
[ERROR] 
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.