updated grammar and documentation

* removed the "like" element from the grammar as well as several other small changes
* documented all elements and attributes and made the documentation look better
* minor updates to the main website
Removed Travis build status from README.md
removed travis build status from index.html
fixed: made pending attribute optional on scenario and expect
added link to xprocspec from grammar specification
namespace cleanup
added license to README.md and link to xproc-maven-plugin in index.html
don't hide buttons on small screens (index.html)
target JAR now has a valid filestructure for CXAN
configured travis for sonatype deployment
.travis.yml fix
declared sonatype repository in pom.xml
added sonatype snapshots as dependency, and staging as target
fixed test1. tested with latest snapshot of xproc-maven-plugin.
disabled xproc-maven-plugin (missing online dependencies)
AddThis toolbox and welcome message

[ci skip]
minor addthis fix

[ci skip]
another minor fix to AddThis

[ci skip]
disable ugly url tracking

[ci skip]
added support for "pending". xspec-style HTML-reports

* scenarios with the pending attribute can now be empty
* the pending element is now allowed within a scenario
* labels are no longer optional
* labels must be non-empty
* the HTML-report has been re-written to match XSpecs HTML reports