Increase mouse scroll speed

By default the scroll speed of Manjaro is quite slow. We can easily increase this with the application imwheel.

For my case I felt Chrome was scrolling way too slow. Fix this I did the following:

# First install imwheel
pacman -S imwheel

# Create profile:
vi ~/.imwheelrc

# Add contents:
None,       Up,     Up,     3
None,       Down,   Down,   3

# Run imwheel