Merged revisions 3729-3829 from 1.7 branch. Fixed serialization of camera nodes, fix array::erase, fix mem leaks in example 22, fix interpolation in SColorf, fix crash in collada loader.

git-svn-id: svn://svn.code.sf.net/p/irrlicht/code/trunk@3830 dfc29bdd-3216-0410-991c-e03cc46cb475