More highlight tidying.

Tidy up highlight calculation.

Use the bounds from the logical highlight shape, rather than
calculating everything from scratch using the text metrics.

Use floats for highlight shapes.

This doesn't help fix anything, but truncating everything to
integers is odd.

Switch count + name in window status.

Fix some container/window changes.

"Tidy up" button bar.

Continue working on Frame Managers

Issue #46

Tidy up window menu

Fixes #62

Move some methods around.

Split methods up to make it easier to read.

Split Close menu item out from WindowMenuFactory.

General tidying of frame managers

Highlight entire line, not just selected chars.

When you select up to the end of the line, we now highlight the
remainder of the line. This means when a block of multiple lines
are selected, the highlight appears as a single contiguous
rectangle, rather than little bits and pieces.

Simplify highlight drawing code.

No need to translate, we can just add some numbers together.

Remove dodgy line height calculation.

Use the proper font metrics to calculate line height and spacing.
For Dialog size 12 (our default font), this seems to be identical
behaviour. Other fonts define more sensible leadings, so are
spaced out properly.

This also fixes highlighting having gaps for large font sizes.

More TextPane tidying.

Change to using Rectangle2D.Float to avoid having to cast all
of the co-ords and dimensions to ints.

Remove a magic 1.5 in the calculations in favour of using the right
properties of the text.

Fix some TextPane layout weirdness.

Stop adding descents all over the place. This stops the highlight
rectangles being slightly offset and allowing descenders to peek
out.

Also adjust the initial Y offset to include padding, and increment
it in the right place.

Unused method.

Make rendering of wrapped lines simpler.