Include all keyboard controls in README

[wong-justin]

A few of the keyboard controls (shift+arrows, g, G, pgup, pgdown, home, end) are not mentioned in the docs. Perhaps these could be mentioned in the readme, especially to clarify the behavior of similar-but-different controls like g vs home?

	Key binding	Description
	Arrows, hjkl	Move cursor
	Enter	Enter directory
	Backspace	Exit directory
	Space	Toggle preview
	Esc, q	Exit with cd
	Ctrl+c	Exit without cd
	/	Fuzzy search
	dd	Delete file or dir
	y	yank current dir
new	g, Shift+up	Move to top of col
new	G, Shift+down	Move to bottom of col
new	Home	Move to beginning
new	End	Move to end

[antonmedv]

Will be cool to add those as well.