Add unsigned int/long type casting pages

[per1234]

• Use C-like type casting syntax in existing cast pages for consistence, since this syntax is required for unsigned int/long
• Add unsigned int/long type casting pages

[cmaglie]

I'd like to keep the Arduino-style byte(..), may we keep both alternatives? maybe adding a note to the new one like:

= byte(x)
= (byte)(x)   (C++ type conversion)

also word now looks a bit weird because it has the helper with two arguments:

(word)x
word(h, l)

if we keep all the alternatives it will become:

word(x)
word(h, l)
(word)(x)    (C++ type conversion)

[per1234]

Thanks for the feedback @cmaglie! I have made the requested change of documenting both casting styles (giving preference to functional notation) via a force push. You can see it in this commit:
c847bd1