ACTIVEMQ6-3 renaming directories from activemq6 to activemq

https://issues.apache.org/jira/browse/ACTIVEMQ6-3

We are renaming packages from activemq6 to activemq as that's more generic and version independent
On this first commit I'm just renaming the directories otherwise the history would be lost. The next commit will rename the text on the directories.
If I squash these two commits git will make us delete / add again.
ACTIVEMQ6-3 renaming package names from activemq6 to activemq

https://issues.apache.org/jira/browse/ACTIVEMQ6-3

We are renaming packages from activemq6 to activemq as that's more generic and version independent
The previous commit renamed the directories. On this commit now I'm changing the code.
If we changed the code and the directories on the same commit git would remove and add a lot of files
without recognizing the renames.
Updated README to reflect new git work flow
ACTIVEMQ6-3 Restoring directories removed by accident on previous commit

https://issues.apache.org/jira/browse/ACTIVEMQ6-3

These directories were removed by accident... restoring them now
ACTIVEMQ6-36 Disallow SSLv3 for POODLE
ACTIVEMQ6-37 NoSuchMethodError during init

When compiled by JDK 8 targeting Java 6 and then run on JDK 6 or 7 the
ConcurrentHashMap#keyset() method can fail because the return types
changed in Java 8. Using ConcurrentMap interface to resolve the issue.
ACTIVEMQ6-38 Overzealous logging for missing queue
ACTIVEMQ6-3 Renaming Exception classes and fixing native compilation

https://issues.apache.org/jira/browse/ACTIVEMQ6-3

The Native Layer has some dependencies on the Exception classes so
I had to rename them now in order to fix the native dependencies
ACTIVEMQ6-4 - more refactoring

https://issues.apache.org/jira/browse/ACTIVEMQ6-4

renamed all the scripts and run commands and variables to be ActiveMQ
ACTIVEMQ6-4 - refactor default configuration

https://issues.apache.org/jira/browse/ACTIVEMQ6-4

Remove the auto generation of the default config and rename to ActiveMQ
ACTIVEMQ6-4 - refactor schemas

https://issues.apache.org/jira/browse/ACTIVEMQ6-4

Refactor all the schemas to use an activemq namespace and rename schema files
ACTIVEMQ6-4 - fix examples

https://issues.apache.org/jira/browse/ACTIVEMQ6-4

some of the examples were broken after the last refactoring.
ACTIVEMQ6-4 - rename all config files

https://issues.apache.org/jira/browse/ACTIVEMQ6-4

rename all the config files to activemq and fix schema names in them