[XBJAPI-51] Integration of the feedback on the 'ReadMe.md' file of the github repository.
[XBJAPI-51] Integration of the feedback on the 'ReadMe.md' file of the
github repository.

Signed-off-by: Tatiana Leon <8c4753e861fecbb16ba9ebac0b105a2d4612071d@digi.com>
GUBotDev/XBeeJavaLibrary,brucetsao/XBeeJavaLibrary,digidotcom/XBeeJavaLibrary