prepare parsing of "application stopped" events (#90)
include "vm operation events" in "event details" tab + adjust "throughput"
upstream merge from 'master'
show / hide "vm operations overhead" in ModelPanel + ModelDetailsPanel based on presence of those events in gc log file
better support for -XX:+PrintGCApplicationStoppedTime

- also parse events without timestamps (pre jdk1.7.0_u50)
- GCModel.totalPause() includes VmOperationEvents pauses
- GCModel.runningTime() includes last pause -> throughput changes slightly
- GCRectanglesRenderer renders VmOperationEvents
- GCRectanglesRenderer draws different colours for different STW events
improve support for -XX:+PrintGCApplicationStoppedTime for G1 algorithm

- parse "application stopped" events without timestamp
- guess timestamp from previous event
Merge branch '#90-application-stopped' (evaluate output generated by `-XX:+PrintGCApplicationStoppedTime` and show in chart / statistics)

addresses issues
- #106 G1; combination of -XX:+PrintGCApplicationStoppedTime, -XX:+PrintTenuringDistribution, -XX:+PrintAdaptiveSizePolicy
- #91 G1; combination of -XX:+PrintGCApplicationStoppedTime, -XX:+PrintTenuringDistribution
- #90 (Oracle Parser without G1); -XX:+PrintGCApplicationStoppedTime
- #25 G1 and others; evaluate -XX:+PrintGCApplicationStoppedTime