Grab latest changes

Small refactor of build server file uploads, and added extra check for 'already uploaded' assets to GitHub

Docs: fence filenames containing wildcards

Docs: Add Contributing doc

CONTRIBUTING.md: Where to find daily installers

Time-index conversion isues with Markers and Keyframes

Exponential zoom levels (and only 14 of them, instead of 800)

Fixing copyright to use translation-friendly formatting, and hiding hardware decode preference (for now)

There isn't actually an "Other Downloads" link on the referenced page anymore, so the previous description was confusing.

(The presence of the "Daily Installers" button on that download page is also confusing, as it does nothing and should probably go away. But that's an issue for the website, not the code.)

Converted from .github/CONTRIBUTING.md with pandoc

Update DPI for Inkscape titles from 90 to 96

Merge from origin master

Updated copyrights to say 2018 (instead of 2016).

Updated copyrights to 2018 (from 2016). Also edited `about.py` so the year is automatically updated.

CONTRIBUTING.md: Be more explicit about logfile paths

Present full path to necessary logfiles under both Windows and UNIX-like systems.

More detailed export dialog progress, including estimate time remaining, FPS, and more accurate percentage. Thanks Peter!

Turns out if the timescale extends beyond 24 hours, weird things happen.

Uncouple zoom level from scale-factor in seconds, make each zoom level
roughly exponential to the previous. (Will actually jump in whole
seconds, minutes, or hours, so 16, 32 seconds will be followed by 1, 2,
... minutes up to 32, then 1, 2, 4, 8 hours -- which is now the maximum.)