Alt key down flag & tag wrapper

New variable flag for altKeyDown just like ctrlKeyDown
Restructured key tracking system into more modular chunks
If CTRL+Alt+key, check if we need to trigger tagWrapper function.
Currently have 8 common tags setup (for div, span, p, a, b, i, strong,
em)
tagWrapper function receives any tag and wraps selected text with that
tag
If it's an a tag tho, it adds a href="" to the start and sets cursor
between quotes