examples: add Interesting snippet tags to examples and link in Readme.md

Signed-off-by: Brendan Le Foll <brendan.le.foll@intel.com>

examples/analogin_a0.c

@@ -31,6 +31,7 @@ int main ()
     maa_aio_context adc_a0;
     uint16_t adc_value = 0;
 
+//! [Interesting]
     adc_a0 = maa_aio_init(0);
     if (adc_a0 == NULL) {
         return 1;
@@ -42,6 +43,7 @@ int main ()
     }
 
     maa_aio_close(adc_a0);
+//! [Interesting]
 
     return MAA_SUCCESS;
 }

examples/cycle-pwm3.c

@@ -30,6 +30,7 @@ int
 main ()
 {
     maa_init();
+//! [Interesting]
     maa_pwm_context pwm;
     pwm = maa_pwm_init(3);
     if (pwm == NULL) {
@@ -49,5 +50,6 @@ main ()
         }
         float output = maa_pwm_read(pwm);
     }
+//! [Interesting]
     return 0;
 }

examples/hellomaa.c

@@ -29,6 +29,8 @@
 int
 main(int argc, char **argv)
 {
+//! [Interesting]
     fprintf(stdout, "hello maa\n Version: %s\n", maa_get_version());
     return 0;
+//! [Interesting]
 }

examples/i2c_HMC5883L.c

@@ -83,6 +83,7 @@ main(int argc, char **argv)
     int16_t x = 0, y = 0, z = 0;
     char rx_tx_buf[MAX_BUFFER_LENGTH];
 
+//! [Interesting]
     maa_i2c_context i2c;
     i2c = maa_i2c_init(0);
 
@@ -90,6 +91,7 @@ main(int argc, char **argv)
     rx_tx_buf[0] = HMC5883L_CONF_REG_B;
     rx_tx_buf[1] = GA_1_3_REG;
     maa_i2c_write(i2c, rx_tx_buf, 2);
+//! [Interesting]
 
     maa_i2c_address(i2c, HMC5883L_I2C_ADDR);
     rx_tx_buf[0] = HMC5883L_MODE_REG;

examples/spi_mcp4261.c

@@ -30,6 +30,7 @@ int
 main(int argc, char **argv)
 {
     maa_init();
+//! [Interesting]
     maa_spi_context spi;
     spi = maa_spi_init(0);
     unsigned int response = 0;
@@ -53,5 +54,5 @@ main(int argc, char **argv)
             usleep(100000);
         }
     }
-
+//! [Interesting]
 }