Let Fx display 'removeOption' correctly

1. Equipment.html: Applying css on <td> might be
problematic on Firefox, therefore we use a <div>
to contain the original content, so that Firefox
can display the "removeOption" button correctly.

2. Equipment.css: Since Firefox does not support
background-position-x/y (only background-position),
and deactivating them seems to make no difference,
therefore I just remove them.

3. WinStats.css: some tweaks.
Let Fx display SkillList correctly
Adjust status align
Make Winstats more like the offical one
Merge pull request #25 from hiunnhue/ui_tweak_fx

Fix css problems on Firefox
Introduce Trade UI / Engine
Fix trade problems

Fix new trade title
Fix overlay position
Fix items quantity received back problem (due to a reference)
Fix Trade item block size and prettify zeny
Fix #28 propagate skill when clicking on minimap/chatbox
Add prompt message when feeding pet
Save pet id for future use.
Prepare function for contextmenu
Remove TODO list.
Merge pull request #29 from vthibault/trade

Introduce Trade UI/Engine
Add support for AutoSpell skill
Complete ItemSelection to support skills
Fix double confirmation when feeding pet
Fix empty title on trade sender
Add support for context menu (for pet and trading)
Clean up EntityControl and MapControl dependencies
Fix #30 - Invalid local files path parsing
Fix #32 - ACTION.SKILL hooked on the wrong packets
Add missing "break", thanks @scriptord3