Update for libsigrok datafeed callback API changes.
Draw numbers off the end of the ruler
deviceoptions.cpp make compile error on 32 bit systems

 fixes compile error: error: no matching function for call to ‘pv::prop::binding::DeviceOptions::bind_int(const QString&, const int&, const char [2], std::pair<long int, long int>)’

Signed-off-by: Joshua Frkuska <j.frkuska@gmail.com>
Added ENABLE_SIGROKDECODE option, disabled for now
Made UNIX signals an optional feature
Replaced std::pair<Cursor, Cursor> with CursorPair
Moved viewport cursor draw functions into CursorsPair
Moved ruler cursor draw functions into CursorsPair
Call sr_session_destroy after loading the SigSession, rather than sr_session_stop
Removed unneeded Cursor::Size constant
Moved Cursor markers to the outside
Added CursorPair::get_cursor_offsets()
Added Cursors Delta display
Renamed SamplingBar::configure to on_configure
Commit the samplerate before beginning to sample
Added missing braces in pv::dialogs::Connect::populate_drivers()
Added proper error handling to pv::SigSession::feed_in_header()
Added error handling to SignalHandler
Add NSIS file for use with cross-compiled PulseView.
Replace GPLv2+ references with GPLv3+.

Most of the PulseView files may be licensed under the GPLv2+, but by linking
against libsigrok (which is GPLv3+) the binary as a whole is GPLv3+.

Reflect that in the COPYING file, the documentation, and the GUI.