Gcc compile fixes.

git-svn-id: http://vtp.googlecode.com/svn/trunk@7818 2ba57974-ef2e-0410-970c-f3cb55f6a86a
Env: fixes to TParamsDlg, add convenience TParams::LayerType()

git-svn-id: http://vtp.googlecode.com/svn/trunk@7819 2ba57974-ef2e-0410-970c-f3cb55f6a86a