Issue #3708

So that tiny mouse motions don't keep resetting the selected item

Closes #3698

Currently operators in most themes look like normal text because
cm-operator doesn't usually get special styling. This patch highlights
word operators (in/and/or/not) to make them stand out better.

Makes sure the selection is not entirely cleared, which causs the
on-screen keyboard to get hidden.

Disabled for Firefox, where this causes other problems.

Issue #3653

Closes gh-3687

for our purposes (=>|<=|...) works just as well as ((<=)|(=>)|...)

... taking the same approach as the C-like page.

Also
- Changes the window title from Oz mode => MscGen mode
- Makes the samples a little more uniform

Closes #3684

Issue #3666

Issue #3682

Closes #3680

And a number of other issues

Which is kind of arbitrary but seems to give less surprising
results.

Issue #3658

Closes #3667

The code is now clearer, and will prefer the nearer end of the atomic
range as long as that means there is still progress (i.e. the cursor
does not get stuck).

Issue #3658

Issue #3624

Closes #3665

So that autoclosing works.

Issue #3660

Issue #3660

This reverts commit 94fc3b71.

Closes #3651

The old behavior sees the closing %} as a haml tag begin. The result
is that the rest of the file after the %} doesnt highlight correctly.

Dont go into quote mode when stream is '{%'.

Clean up weirdly specified regexps

Closes #3641