Add a CustomFieldserializer abstract implementation.

It is to be on a par with CustomObjectSerializer and its abstract
implementation (and to have an example of how a CustomFieldSerializer can
be done).
small fixes
Fixed LazyMap bug
#209
Merge pull request #215 from Tugdual/custom_field_serialization

Add a CustomFieldserializer abstract implementation.
[maven-release-plugin] prepare release boon-0.25
[maven-release-plugin] prepare for next development iteration
Fixed some bugs. Added some examples. Responded to some Boon folks.
#180 closed
#179 seems to handle it well.
Fixed issue #179
Fixed issue #216 This time for real.
#107
#217
#220 #219 #218
Messed up. Test issues. Fixed now.
Utility for starting thread pools with names by default
Added more stats.
Added two more utility functions.
more metrics