AppenderBase started variable made volatile

AppenderBase started variable made volatile as it is mutable, access to it is not synchronized and it is shared between threads.
Fix for http://jira.qos.ch/browse/LOGBACK-1037

Fix for Prudent FileAppender and thread interruptions (LOGBACK-875)

Prevent logging on an interrupted thread from shutting down prudent file
appenders due to a FileLockInterruptedException

This reverts commit 147ed05b.

AsyncAppenderBaseTest: The appender was not allowed enough time to
flush the appender on #stop(), causing the empty-check of the appender's
queue to fail. The test appender's max-flush time is now extended from
30ms to >1000ms.

AbstractSocketAppenderIntegrationTest: A unit test expected
deque.takeFirst() to be called only once after a log-event is appended,
but the call actually occurs twice in a while-loop, where the second
call is intended to block, waiting for the next log-event.

AbstractSocketAppenderTest: A unit test that verified appender
behavior when its deque was at capacity neglected to fill the deque
before testing for errors.

Added note for LOGBACK-128

Add notes for #193 (LOBGACK-977), provided by Sebastian Gröbler

LOGBACK-977 - AbstractSocketAppender loses event for every socket connection break

extended documentation to reflect new SocketAppender behaviour towards synchronous/asynchronous queueing

* made AbstrackSocketAppender not lose events when socket connections gets lost (now uses LinkedBlockingDeque)
* extracted aspects of deque creation and output stream creation to factories in order to improve testability
* ecapsulated automatic flushing of output stream into a separate class in order to make this functionality testable
* slightly refactored internal structure of AbstrackSocketAppender to improve maintainability

Warn users against adding their release notes to news.html since that
always causes merge conflicts.

Moving access request log configuration in to its own method to allow extension

Make prepareForDeferredProcessing on AccessEvent idempotent, otherwise the OutputStreamAppender overwrites valid properties with now invalid properties when using an async appender

Update gmaven to gmavenplus plugin

When Multiple FileAppenders attempt to write files to the same
nonexistent directory, concurrent threads could attempt to create
the directory at the same time, where only one succeeds, while
the others hit an IllegalStateException. This patch modifies
FileUtil.createMissingParentDirectories() to gracefully handle
existing directories (no exceptions thrown).

This patch also removes FileUtil.isParentDirectoryCreationRequired()
as this allows for race conditions between the existence-check and
the directory creation. Note that File.mkdirs() already performs
an existence-check.

Fixes LOGBACK-128

Updated to newer groovy maven plus plugin
Switch from deprecated ant 'tasks' to ant 'target' maven xml tags

Fix for LOGBACK-732, make charset configurable in SyslogAppender

* Add setCharset()/getCharset() methods to SyslogAppenderBase
* Add blurb to news html page
* Unit test

This change change takes the conservative approach of preserving current
behavior when setCharset() is not called, using the platform default encoding.

Add git attributes - to fix line endings

Add suggested git attributes and associated files that were not in sync
already with expected line endings.

moved remaining resources to src/main/resources

logback-access & logback-examples resource files moved from source
packages to resources packages to comply with maven standards.

Added note for the move of the SQL scripts to src/main/resources
from Jeremy Landis (PR #197) (LOGBACK-948)

moved db appender scripts to src/main/resources

moved db appender scripts to src/main/resources (duplicate of #190 -
cleaner)

POM Modernization

- Corrected maven xsd
- Removed duplication in child poms (url, license, version, groupId)
- Removed commented out scala items
- Removed commented out jetty servlet api
- Removed excess spacing
- Note JavaSE-1.6 & 1.6 oracle docs
- Replaced examples use of antrun with maven-dependency-plugin
- Updated plugin versions
- Added plugins in parent pluginManagement
- Updated mockito & log4j
- Dropped old slf4j-api 1.5.10 - pom pulls latest
- Moved modelVersion to correct location
- Explicit groupId everywhere
- Use maven properties for jdk version used for compiler plugin
- Added generation of test source & javadoc jars
- Added lifecycle mapping filter for gmaven for users without m2e configuration.
- Moved maven bundle to plugin management