Update install-mac-linux.sh

[elliot-huffman]

Added prompt to ask user where the Android SDK is located (to set the android_home var)

Added quotes around "$ANDROID_HOME%\platform-tools\adb" in case of file paths with spaces.

Added "#" comments for ease of debugging

Added functions to separate code into sections for ease of debugging

added initialization

Rewrote initialization so that ANDROID_HOME is cleared for compatibility.

Fixed wording so that the disclaimer section is more readable.

Added a proper bash exit for compatibility with other automation programs (or scripts)

[elliot-huffman]

I also found the "pause" command in the code so I replace it with the appropriate Linux/Mac equivalant

[johnnyapol]

Checked this out on my Ubuntu box and looks great. Thanks!