Replace *CellDraw classes with CellFormatting functions.

This fixes rendering and crashing issues in (Rom|Game)Grid with mono.
Need cellbounds to be the full wide and not just the visual.
Move (Rom|Game)Grid CellFormatting functions to be in the right #region sections
Make drawn text look better in GameGrid's CCorrect
GetFiles() for mono was missing initializing the Length
speed up populating GameGrid

These changes speed up how long it takes to populate the GameGrid after
clicking on a dat in the Tree.  MAME 0.155 dat was used for testing.
Before the changes population times were

windows .net = 2.75 seconds
linux mono = 23 seconds

After the changes, both now take 300-400ms.

This was done using 2 main changes.

1. Fully move populating the rows' Values to the CellFormatting function
2. Determine the total number of rows we will need and use
GameGrid.rowCount to set the row count to that.  This is much faster
then doing individual Add()'s for each row.
Merge pull request #6 from jwestfall69/mono-ui-fixes

Mono UI/Crash fixes