*boruta_modbus: change def registers timeout

defualt value for timing out registers in 1 minute
(instead of no time out at all)
*wx/draw3: show values diff for double cursor

while in double coursor info widget also shows difference
between valus at the beginning and end of range
*wx/draw3: small new feature

Pressing right mouse button on graphs widgets switches
widget to double cursor mode. Moving the mouse, with
right button still pressed, makes the graph cursor
to follow mouse pointer. When the right mouse button is
relased widget switches back to non-double cursor mode.

+ 2-3 compilation warnings removed
Merge branch 'master' of https://github.com/Newterm/szarp
Remove English draw3 documentation build

+ revert changes from 053d4a which causes build fail
bugfix: ipk2szarp sometimes failed to check repetitions

+ ipk2szarp sometimes didn't report verbosely that there were duplicated
  parameters in base
+ it was also sometimes counting duplicated parameters wrong
Change szarp update policy

+ szarp wont be updated automatically from Friday till Sunday
building stable
Merge branch 'master' into devel
building unstable