Double-click word feature + scroll bug fix

[A.P. Sillers]

I've written up a rough draft of a feature that allows player to
double click on a word in the story text to add it to the input line.
(I thought this was a requested feature in the Google Code bug
tracker, but I can't find it now. I believe mobile versions of Frotz
do this.) I've committed it to my fork of Parchment on Github
[https://github.com/apsillers/parchment/commit/
10bd9b1e2b3be15e217e3f4f5f3c96226243a28e]. I have *not* tested it
with Glulx games.

I was trying to make a pull request to the mainline Parchment repo,
but I'm still learning git at the moment, and I can't do it without
including other (unrelated) changes in the pull request. Anyway, is
this something you're interested in including in Parchment?

Also, there's a bug that breaks scroll-to-the-bottom behavior after
submitting a command in WebKit. There's a variable called
"bodylineheight" set to the "line-height" CSS property. Right now,
parchment assumes the line-height property is a pixel value, which is
true by default in Firefox, but WebKit sets line-height to the string
"normal". Parchment fails to get the pixel value out of line-height,
which breaks the scrollTo operation that uses bodylineheight. My fix
can accept a pixel value, ratio, or "normal" for line-height. The
commit is at https://github.com/apsillers/parchment/commit/e6de62ffa3095cafcbeb2d1684313dde0c4df4bb.

Once I figure out git, I'll make a pull request, or you can just grab
the diff off Github instead.

--aps

[Dannii]

Thanks for those!

I'll wait for later for the double click feature... mobile Parchment is nowhere near ready yet.

For the other bug thanks for finding its source. I'll fix it differently (I'll just make a temporarily element and measure it). It's for a compatibility function so I'm not too concerned if it's not perfect, as long as it's good enough.