change instructions for CustomSymbols sort order

The previous recipe did not work. It seems that the initial copy of
the .bmp files has to be delayed.
data update (minor)
check for imagemagick / convert tool first
basic test for typ2legend
add imagemagick as a prereq for travis-ci
import changes in bundled modules

Http: version 4.02, which has a fix in Host header handling
Tk::WidgetDump: removed self-test code
Win32Util: new function get_volume_name
GPS::BBBikeGPS::MountedDevice: support for Windows
remove unused $PROG_REVISION
Merge remote-tracking branch 'eserte/master' into world