Only do gradle check for pull requests

Prior to this commit pull request builds would fail in Travis CI due to missing credentials (for security reasons). This commit limits the builds for the pull requests to the 'check' task to make sure that it builds and that all tests passes.
Merge pull request #375 from bjornerik/travis-pr

Only do gradle check for pull requests
Upgrade to Gradle 1.12
Merge pull request #376 from spring-io/gradle-1.12

Upgrade to Gradle 1.12
Enable the Spring Boot remote shell
Fixes invalid value for ddl-auto

Prior to this commit the property spring.jpa.hibernate.ddl-auto was set to 'false', not a valid value for that property - and a warning was issued by Hibernate. The wanted behaviour is to have "no automatic DDL actions", so the correct is to set it to the (undocumented) value 'none'.
Exclude Commons logging and Log4j from dependencies

Sagan is set up with Logback as the logging framework, with Slf4j bridges from Commons logging, log4j and Java Util logging. Prior to this commit both log4j and Commons logging were included in the dependencies. Commons logging seem to get routed fine to Slf4j, but with libraries using Log4j or JBoss logger (used by Hibernate) it seem to be random due to class loading order (mostly not).

This commit exclude both Log4j and Commons logging from the dependencies.
Revert "Enable the Spring Boot remote shell"

This reverts commit c36fc1a421f17dc487ec11b3f6aaace1ea5f0666 as a
potential remedy for #378.
Merge pull request #373 from bjornerik/logging-cleanup

Exclude Commons logging and Log4j from dependencies
Merge pull request #365 from bjornerik/fix-ddl-auto

Unrecognized property value for spring.jpa.hibernate.ddl-auto
Fixes invalid value for ddl-auto in sagan-site

Change spring.jpa.hibernate.ddl-auto from 'false' (invalid) to 'none' in sagan-site. This was previously fixed in sagan-indexer (see #365), but missed this one.
Attempt to add Disqus comment count

Per instructions at http://help.disqus.com/customer/portal/articles/565624
Remove #disqus_thread from href
Assign value of ${post.id} to data-disqus-identifier
Use protocol-relative URL syntax to fetch Disqus JS
Add css to show comment icon on blog index page

Also, updated iconsprite with latest version which includes the icon
itself.
Add comment count to blog post page
Merge pull request #383 from bjornerik/fix-ddl-auto2

Fixes invalid value for ddl-auto in sagan-site
Merge pull request #339 from spring-io/comment-count
Update tests to reflect GitHub's new path to raw content

The dynamic sidebar tests use macros, which are located on github via
raw URLs. When they changed their path, it didn't cause any failures
while also slowing down the tests (see #369).

This commit updates the tests to use the new paths and also added a
check to verify that macro content was actually loaded. Both should
cause a more recognizable failure if github makes similar edits.

The impact is that all the guides need to be updated to reflect the new
paths.