Loads of updates/fixes. Everything is now zero-based (positions, columns,

Loads of updates/fixes. Everything is now zero-based (positions, columns,
line numbers, insertion points, the whole business). SetInsertionPoint now
works, sort of. It doesn't move the actual cursor, but WriteText will
insert at the newly set insertion point (after which the cursor is moved
anyway). This should be good enough for most uses. See further comments
in the source. BTW, WriteText now inserts text at the current point (used
to append to the end only).

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@1530 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775