[Bug #1545726] Incorrect FSF address in many extension files.

Extensions. Fix for bug #1496804 (Flatten Beziers: raise lower limit for flatness factor to prevent endless loop in python script)

Super duper mega (fun!) commit: replaced encoding=utf-8 with fileencoding=utf-8 in all 1074 Vim modelines. The reason for this is that (a) setting the encoding isn't nice, and (b) Vim 7.3 (with modeline enabled) disallows it and pops up an error whenever you open any file with it ("invalid modeline"). Also corrected five deviant modestrings: * src/ui/widget/dock.cpp and src/ui/widget/dock.h: missing colon at the end * src/ui/dialog/tile.cpp: removed gratuitous second colon at the end * src/helper/units-test.h: removed gratuitous space before a colon * share/extensions/export_gimp_palette.py: missing textwidth=99 That's my geekiest commit yet.

share/extensions/*.py: Wrap ‘e = MyEffect(); e.affect()’ in ‘if __name__ == '__main__':’, to allow use of pychecker.

noop: Add vim modeline for all share/extensions/*.py files that use four-space indentation.

Another round of extension conversion (from pyxml to lxml) and some corrections

standardize indents on 4 spaces Python hates mixed whitespace

adding an effect to flatten curves by breaking them into sufficiently flat line segments