do not attempt to clean relations
permanent fix for e8a3ad0b5e2b9183932acebe973ff276d94de803
fixed many-to-many relation not using write connection
Merge pull request #331 from SlKelevro/fix-relations-connection-usage

fixed many-to-many relation not using write connection
added methods to enable/disable defined observer events. related #330
make sure the before_save observer is called before checking the diff; closes #330
remove static from method definitions
bumped the copyright to 2014
Makes Soft_Delete::purge() actually delete models
fixed passing custom data to a model constructor; fixed as_object() instantiations not cached

thanks for @keigoi for spotting the custom data issue (see #332)