[bb] Land Flattener

Why this tool?
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There's a few land flattening tools out there but two things bothered me about the ones I found:

* They turned on as soon as you rezzed them, which could be annoying and potentially catastrophic to your build
* They often come with three sizes, which is entirely unnecessary inventory clutter.

Thus, I created this simple tool to be a more contextual, user-friendly land flattening tool. Like most things i make, I made it because I use it myself. Hopefully you will find it useful as well.

Features:
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* Turn ON or OFF -- useful for moving it without messing up land you don't intend to change.
* Long click to resize -- no need for three separate tools in different sizes. This one can change on the fly, just long click it!
* Contextual hover text to make it easy to see your settings.

Instructions:
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* To use this tool, simply rez it and move it to the place you want to begin flattening.
* Single click the tool to turn it on or off
* Long click to choose size:
- Small is 2m²
- Medium is 4m²
- Large is 8m²
* Drag the tool around from the edit menu to level your land!

Obvious caveats:
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* You must have terraform rights on the land you wish to edit. It will fail silently if you do not.
* You cannot raise or lower the land more than the limits baked into your parcel or sim.