Update ssd1306_128x64_i2c.ino

The Spark IDE doesn't compile with function name random, so changed it to arandom

Replaced unsigned char 'logo16_glcd_bmp' with 'LOGO16_GLCD_BMP' so that spark IDE can compile.
Merge pull request #2 from prahaladm/patch-1

Update ssd1306_128x64_i2c.ino