NumbersUtil cleanup

- removed methods that were not used
- parseLong, parseInt and parseFloat replaced with the commons-lang NumberUtils call
- Test for the remaining methods

Signed-off-by: Laszlo Hornyak <laszlo.hornyak@gmail.com>
Signed-off-by: Hugo Trippaers <htrippaers@schubergphilis.com>
Add Manage Context framework

The managed context framework provides a simple way to add logic
to ACS at the various entry points of the system.  As threads are
launched and ran listeners can be registered for onEntry or onLeave
of the managed context.  This framework will be used specifically
to handle DB transaction checking and setting up the CallContext.
This framework is need to transition away from ACS custom AOP to
Spring AOP.
Merge branch 'managed-context' of github.com:ibuildthecloud/cloudstack into managed-context