remove cruft (unused) lib dependencies.

See #422
Update version to 1.6.0-0-SNAPSHOT
Initial logging system revamp
Add test for LogEntryLineIterator

Test legacy fallback dateformat
Update rundeck log format, add tests
Update log stream interfaces

add openStream interface
use pending state if file doesn't exist yet
Catch exceptions for plugins
Initial plugin usage for streaming

streaming log reader plugin implementation

allowing multiple writer plugins

Fix some type checks, update event map structure from plugins
rename LogEvent property to loglevel from logLevel
Update use of loglevel property of LogEvent
Fix potential npe if event data has null message
Simulate tail mode in browser if necessary
de-emphasize non other level log output
Update time display in output
Fix potential NPE if metadata is null
Filter log events for executions by level threshold
Add example code
Change streaming log writer interface to add initialize method

* wrap plugins in more durable mechanism to catch errors
Allow configuration to disable local file log stream