Fix getTINT() return

[caternuson]

For #27.

Just changes local variable types to long to match return.

Fixes issue on UNO. Some output from example sketch in issue thread:

Current ATIME for sensor : 200
Current ASTEP for sensor : 600
Current GAIN for sensor : 1
Current TINT (ms) for sensor : 335
TINT calculated 335
Reading ADC4/Clear    : 45
Basic counts ADC4/Clear    : 0.13
Basic counts semi manual for sensor : 0.00
Basic counts manual for sensor : 0.00
Current ATIME for sensor : 225
Current ASTEP for sensor : 600
Current GAIN for sensor : 1
Current TINT (ms) for sensor : 377
TINT calculated 377
Reading ADC4/Clear    : 51
Basic counts ADC4/Clear    : 0.14
Basic counts semi manual for sensor : 0.00
Basic counts manual for sensor : 0.00
Current ATIME for sensor : 250
Current ASTEP for sensor : 600
Current GAIN for sensor : 1
Current TINT (ms) for sensor : 419
TINT calculated 419
Reading ADC4/Clear    : 57
Basic counts ADC4/Clear    : 0.14
Basic counts semi manual for sensor : 0.00
Basic counts manual for sensor : 0.00

Focusing on lines that matter, for example, these two lines agree now:

Current TINT (ms) for sensor : 419
TINT calculated 419

[caternuson]

@ladyada for review

[ladyada]

good find!