Engine3.01 released

Loads of xml comments still to be written/re-written to reflect all changes

Changes in this release
================
I will always list the changes under the classes that have been affected (I will keep them in alphabetical order)

EngineManager
==========
added - if you show any engine debugging information the version of the engine you are using is displayed.

LayerManager
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renamed LayerAdd() to Add() - this will affect Adam and Joe

TextManager
=========
added - TextManager.DrawQuick(), this allows you to draw no frills text, horizontal with colour,scaling and alignment. This is very much faster than the standard text drawing routines (which do a lot of complex formatting and rotating).

developed - Done some speed ups of complex text rendering methods still lots of room for improvement. (edit)

TileSheet
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implemented - ScrollScale factor when moving layer with viewport position. This already happened automatically when scrolling was applied to a TileSheet.

investigate - Draw() draws too many tiles still, need to work out full calculation so we can keep tiles drawn to a minimum, this is a problem with non regular size layers

TrackManager
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developed - TravelWithSpeed works but needs some work as seems disproportionate with different tracks pixel lengths!

fixed - moving between tracks now works out where you will join a track rather than place the sprite at position 0 (or end position).