[examples] Build examples with '-g -O0'.

We do not need to optimize examples, nad it is good to have them
easily debuggable.
[TREELIST] Support for dynamically populated trees.

 * Added notifications MC_TLN_EXPANDING and MC_TLN_EXPANDED.
 * Added MC_TLITEM::cChildren.
 * Added documentation section about it.
[TREELIST] Exchange meaning of WPRARAM and LPARAM for MC_TLM_DELETEITEM.

This makes it to follow treeview.