Fixed issue #145 GPIO library doesn't free GPIO file descriptor. File descriptor leak.

[Red-Eyed]

Fixed issue #145 GPIO library doesn't free GPIO file descriptor. File descriptor leak.
Made a little bit refactoring.

[Red-Eyed]

I did strace and what I saw:
I was looking at these logs for about 10 min and leds continued blinking.

select(0, NULL, NULL, NULL, {0, 100000}) = 0 (Timeout)
access("/sys/class/leds/beaglebone:green:usr1/brightness", W_OK) = 0
open("/sys/class/leds/beaglebone:green:usr1/brightness", O_WRONLY) = 4
write(4, "1", 1)                        = 1
close(4)               

[pdp7]

Thanks for the fix. I'll test it out.

[pdp7]

pytest completed OK.

debian@beaglebone:~/pr/adafruit-beaglebone-io-python$ sudo pytest
============================================================================ test session starts ============================================================================
platform linux2 -- Python 2.7.9, pytest-3.1.2, py-1.4.34, pluggy-0.4.0
rootdir: /home/debian/pr/adafruit-beaglebone-io-python, inifile:
collected 58 items 

test/test_adc.py ......
test/test_gpio_input.py ..
test/test_gpio_output.py ......
test/test_gpio_setup.py ..........
test/test_led.py ..
test/test_pwm_setup.py ...........................
test/test_spi.py ..
test/test_uart.py ...

========================================================================= 58 passed in 3.46 seconds =========================================================================

[pdp7]

Thanks @Vadim-Stupakov