Problem: Hints aren't displayed for certain elements. This was because
the isVisible function didn't pay attention to the element's 'display'
attribute when deciding whether an element is visible according to its
height/width.
Solution: Add two functions to help decide whether the height and width
attribute of an element matter.
Note: The two functions do not do anything if an element's 'display'
attribute is set to either 'initial' or 'inherit' because taking these
into account seems complicated.
Fixes issue https://github.com/cmcaine/tridactyl/issues/127 .
The DOM.getElemsBySelector function makes it a bit less verbose to
construct an array of filtered elements matching a selector.
Also, this function is expanded to take multiple filters, applied
sequentially.
Can focus the nth input from the start or end of a page.
Also has some special modes:
-l: last focussed input
-p: first password input
-b: the largest input by area
exmode.parser now converts strings to the types given in excmd
signatures.
Messaging now works in both directions (but I haven't made excmds.ts use
the new system yet. Exercise for the reader (see keydown_* state() for a
simple example)).
keys are now being suppressed, but in a pretty stupid way.
I got fed up of not having proper itertools, or str conversions, so I
wrote some. Others have written them in JS, but they were fun to make.
Only the ones I'm using are tested.
