Add block parameter to FindValueInArray native.

I'm not sure what is going on with trailing whitespace/line endings in this file, my apologies for making that diff crazy.

I guess there's no easy way to test, but I did a small test myself:

```
#include <sourcemod>
public OnPluginStart()
{
	Handle arr = CreateArray(2);

	PushArrayCell(arr, 10);
	PushArrayCell(arr, 20);
	PushArrayCell(arr, 30);
	PushArrayCell(arr, 40);
	SetArrayCell(arr, 0, -10, 1);
	SetArrayCell(arr, 1, -20, 1);
	SetArrayCell(arr, 2, -30, 1);
	SetArrayCell(arr, 3, -40, 1);

	LogMessage("result = %d", FindValueInArray(arr, -999));    // should be -1
	LogMessage("result = %d", FindValueInArray(arr, -999, 0)); // should be -1
	LogMessage("result = %d", FindValueInArray(arr, -999, 1)); // should be -1

	LogMessage("result = %d", FindValueInArray(arr, -30));    // should be -1
	LogMessage("result = %d", FindValueInArray(arr, -30, 0)); // should be -1
	LogMessage("result = %d", FindValueInArray(arr, 10, 1)); // should be -1
	LogMessage("result = %d", FindValueInArray(arr, -10, 1)); // should be 0
	LogMessage("result = %d", FindValueInArray(arr, -30, 1)); // should be 2
	LogMessage("result = %d", FindValueInArray(arr, -40, 1)); // should be 3

	CloseHandle(arr);
}
```
```
L 12/06/2014 - 09:12:37: SourceMod log file session started (file "L20141206.log") (Version "1.7.0-dev+5061")
L 12/06/2014 - 09:12:37: -------- Mapchange to de_dust --------
L 12/06/2014 - 09:12:37: [test.smx] result = -1
L 12/06/2014 - 09:12:37: [test.smx] result = -1
L 12/06/2014 - 09:12:37: [test.smx] result = -1
L 12/06/2014 - 09:12:37: [test.smx] result = -1
L 12/06/2014 - 09:12:37: [test.smx] result = -1
L 12/06/2014 - 09:12:37: [test.smx] result = -1
L 12/06/2014 - 09:12:37: [test.smx] result = 0
L 12/06/2014 - 09:12:37: [test.smx] result = 2
L 12/06/2014 - 09:12:37: [test.smx] result = 3
L 12/06/2014 - 04:12:39: -------- Mapchange to workshop/122443683/aim_map --------
```