Fix typos.
Adding support for Throwable.getSuppressed().

See http://www.oracle.com/technetwork/articles/java/trywithresources-401775.html

- Removed superfluous public from methods in IThrowableProxy interface and added method IThrowableProxy[] getSuppressed().
- Serialized ThrowableProxyVO will be incompatible since suppressed has been added. Consequently, the respective serialVersionUID has been changed.
- ThrowableProxyVO.equals is now also checking suppressed.
- ThrowableProxy is now evaluating suppressed Throwables of its c'tor argument if the Throwable class has a getSuppressed() method, i.e. in case of Java SE 7 and upwards.

This patch is merely adding support of suppressed exceptions to the creation of LoggingEvent/IThrowableProxy. Further support should be added to the following classes:

- ch.qos.logback.classic.db.DBAppender
- ch.qos.logback.classic.html.DefaultThrowableRenderer
- ch.qos.logback.classic.net.SyslogAppender
- ch.qos.logback.classic.pattern.ThrowableProxyConverter
- ch.qos.logback.classic.spi.ThrowableProxyUtil
  - method asString
- ch.qos.logback.classic.spi.PackagingDataCalculator
  - method calculate(IThrowableProxy tp) may also need to take suppressed into account.
http://jira.qos.ch/browse/LBCLASSIC-275 - LoggingEvent casts to LogbackMDCAdapter without checking
Implementation of the proposal in the first comment of that issue: defer reading the MDC until as late as possible
Calculating packaging data for suppressed Throwables.

calculate(IThrowableProxy), as expected, needs to support suppressed Throwables, too.

All of this has been tested with Java 7 b145 and is working as expected.
fix typo: mdcPropertyMap != null should have been mdcPropertyMap == null
proper handling of null MDC in LoggingEvent caching
Merge branch 'typo_fixes' of git://github.com/datafueled/logback
Preparatory work for fixing LBCLASSIC-265. The first step is to detect
SAX exceptions during Joran doConfigure invocation.
fixed LBCLASSIC-265
configuration recovery works with included files as well. Fixes LBCLASSIC-265
Allow multiple recipient address in 1 <to> element in SMTPAppender (LBCORE-213)
Merge commit '2b2edb0cc0d0e8c3f8c26a39e40811181aa4f63'
blurb about multiple email destinations separated by commas
fixing LBCLASSIC-273
Fix for:

    http://jira.qos.ch/browse/LBCORE-214

I took the simple route and handled only the case that applies immediately to the issue mentioned in the bug.  I made no attempt to handle literal single quotes as thas would complicate the parsing needlessly.
Merge pull request #19 from dlibby00/master

FIx for LBCORE-214
minor clean up
minor edits
typo fixes
added a link to the logback-akka project