qwt: update to 6.1.1
qwt: more files from updating to qwt 6.1.1
qwt: remove outdated constants

This is a pending change from qwt-6.1.2, and is needed to
support Qt 5.4
qwt: update qwt qmake files to build and link properly

fixes the target name, drops some unnecessary constants, etc.
scopes: adapt to renamed qwt 6.1 'set*Pen' methods
scopes: updates for qwt 6.1.1

There should be no change in functionality. How we interact
between the legend and plots had to change.
Release: tag windows portable and installers separately
Autotune: fix typo in UI
Bootloader: allow altering the startup delay

For boards without a vsense pin, it is necessary to have
sufficient delay to allow enumaration (500 ms). For boards
with a VSENSE pin this can be overridden to a shorter
period.
Sparky: use 2 ms bootloader delay

This allows Spektrum binding. Also, it bumps the bootloader
revision to 0x83.
Quanton: use 2 ms bootloader delay
Colibri: use 2 ms bootloader delay
RevoMini: use 2 ms bootloader delay
Merge pull request #1378 from peabody124/small_fixes

Small fixes
Merge pull request #1374 from peabody124/qwt_6.1.1

Upgrade to Qwt 6.1.1
Merge pull request #1385 from peabody124/spektrum_binding

Spektrum binding