Re-implement commit that converted info for Sprites for the level editor in a struct. This had to be reverted when merging the branches because it didn't get in the new branch.

Original commit hash: 4bb06bca97599d7c9f21f0fed1ab04477bf8fb7b
Original commit message:Implement method to determine whether or not a tile is collidable, ignores the grid positioning and has a priority in being drawn (last part is NYI).
Level Editor: holding shift when placing a tile will no longer make you lose your current selection.
Fix collision detection for player in the level editor. Switched one X and Y co-ord.. :)
Add a file 'inlinefunctions.hpp' which will contain defines/enums/structs/etc. that will be used all over the code.
Level Editor: Implement a 'clear' button to empty current set of tiles added and rename the enable_grid.png image to toggle_grid.png.
Level Editor: Use a VertexArray of LinesStrip rather than a sf::RectangleShape to draw the grid. The line thickness of the RectangleShape couldn't get smaller than 1.0f, which is WAY too thick for a simple 'background' grid. Plus I wanted to play a little with lines. :)
Work in progress, code with care :P