Sync bluMouseEvents with its latest version

Fixes a few minor issues, nothing immediately relevant to PD.  Also:

- now that the original project is on GitHub, supplied a link and
instructions to download that for outside use
- search+replace some items to simplify the text and roughly match the
coding style of the rest of PD (no unnecessary keywords, etc)
Move ESC-to-cancel checks into the main processor function

Note: I still need to add Undo-rollback code
Move the old toolbar module into Interface, and rename old functions

In way old versions of PD, the toolbar module and accompanying tInit
function were used to enable/disable multiple controls based on meta-
labels, e.g. "Undo" which requires a number of menu items and toolbox
buttons to be triggered.

Because I no longer have a toolbar, and tInit is not very descriptive,
I've moved the code into the more-appropriate Interface module and
renamed associated functions to match.
Separate various "add transparency" options

Placing so many transparency options on the same dialog was a dumb idea.
PD tries to adhere to the "do one thing and do it well" rule for tool
dialogs, so I've separated out the "green screen" option into its own
tool.  This also makes it far more discoverable.

A few other items in this commit.  I now allow "add alpha channel" tools
to be used on 32bpp images, as it may be useful to modify an existing
alpha channel.  "Remove alpha channel" is still disabled for 24bpp
images.

Also I've rewritten the Image -> Transparency menu to exclusively use
"transparency" instead of "alpha".  This is in keeping with the Options
dialog as well.

Finally, both add alpha dialogs have been converted to use the command
bar.
Properly reset Undo data when ESC is pressed mid-process

(Technically this should have been required to successfully close #58)

Undo data is now rolled back to its proper state when ESC is used to
cancel an active action.  A few implementation notes:

- Macro recording will still record the canceled action.  (There's no
good way to handle this, short of flagging canceled actions and removing
them at macro save-time, which seems like overkill for such a fringe
use.  I'd rather just wait until I have a GUI for macro editing and
tackle this then.)

- Fade Last Effect is still enabled, and will use the proper data

- Perhaps confusingly, Repeat Last Action will repeat the canceled
action (as it was the last one performed).  I like this behavior as a
person may think "eh, maybe I'll go ahead and try it again".

- If the action was initiated mid-way through the Undo/Redo chain (e.g.
the user had pressed Undo prior to initiating the canceled action), the
user will still lose all actions past that point (e.g. Redo will be
unavailable).  This is desired behavior, as all subsequent Redo data
will have already been erased when the canceled action was first
initiated.
- I have not yet tested how this plays with the custom ESC-to-Cancel
behavior during batch processing.  That is on my to-do list.