dropped print command from file menu

- it was kind of an attractive nuisance since you’ll inevitably get
better results by pulling an exported image into, say, illustrator or
preview
added CALayer to imports
shortened view classnames
now using layer-based display pipeline

- the GraphicsView now uses core animation layers to cache the script’s
output (rather than manually blitting a cached nsimage)
- disabled elastic scrolling in the graphics view
- restored support for tiff/eps pasteboards
- was able to unflip all the views (since the coord transforms are
handled by the canvas itself when it generates the bitmap)
- curious to know whether this causes a regression on retina displays…
moved XMLParser to .util
read() now handles urls without a Last-Modified

- though really the cache-handler should know about etags too…
for future reference
new aat_attrs() util

- converts from lig/sc/osf/etc kwargs to coretext features suitable for
an nsattributedstring
additional typography imports
BoundsMixin now handles None correctly

- it was raising exceptions when instantiating Text objects without
fixed dimensions
typos & url updates
oops. shouldn't have unflipped the views
no longer keeping track of NSFont ‘traits’
font arg parsing now much saner
revamped typography subsystem

- added font() args for opentype/aat features controlling ligatures
(lig), small caps (sc), number case (osf), number spacing (tab),
sub/superscripts (vpos), and automatic fractions (frac). all the args
can be set to booleans or 0/1
- the `lig` and `sc` args can also be set to `all` (the keyword, not a
string) to enable rare ligatures and to small-capify both u&lc
respectively
- the new `tracking` arg sets letterspacing in thousandths of an em
(same scheme as in the Adobe apps)
- font() and text() can both take an `align` arg now rather than having
to set it through the align() command
- switched the default typeface to Helvetica Neue
- made Font objects immutable
added arg validation for the aat features
clarified the font `tracking` arg

- setting it to zero means `no adjustment’ whereas setting it to None
means `disregard all the kerning pairs in the font itself’
coming attractions
redundancy
fixed shell-detection routine

- home directories that weren’t using the standard  /Users/someone
scheme were confusing the directory-services query