update bundled WWWBrowser.pm to 2.51
tkpod: -geometry now works

tkpod is creating a hidden MainWindow, which is "eating" the -geometry
option. To fix this, a prescan of the cmdline arguments is done before
creating the MainWindow, remembered, and applied to Pod windows
created later.
test suite works with WMs with interactive geometry placement

I.e. running the test suite with ancient twm works now.
enable travis-ci