Fixed launching of Trev to avoid knowing the wish executable name.


git-svn-id: svn://svn.code.sf.net/p/staden/code/staden@3553 ba6f2710-ca9f-427c-89d3-5bf716dbc8e1
Use text_utils instead of tk_utils as vector_clip was inheriting a
dependency on tk86.dll which bizarrely then crashes on program exit.

The reason we switched to tk_utils instead of text_utils was, I think,
originally due to inanities of the macosx linker disallowing linking
against seq_utils and tk_utils within, say, gap4. But both that and
windows now work.


git-svn-id: svn://svn.code.sf.net/p/staden/code/staden@3554 ba6f2710-ca9f-427c-89d3-5bf716dbc8e1