Feature modify board sim

[HgonKim]

• use lower case for package (irSensor => irsensor).
• delete the 'lightRGB' package.

[HgonKim]

• Each name of the folder and files related to is changed to lowercase.
• Delete the 'lightRGB' package.
• We will edit your previous [pull request] comment later.

[HgonKim]

Because of merging branch 'feature-robotis_block_make' into feature-modify_board_sim, pxt-build is failed. So, this PR is closed.