Before:
 * << is left shift, not allowed to shift 1 bits out
 * <<% is left shift, allowed to shift 1 bits out
 * >> is right shift, allowed to shift 1 bits out

After:
 * << is left shift, allowed to shift 1 bits out
 * >> is right shift, allowed to shift 1 bits out
 * @shlExact is left shift, not allowed to shift 1 bits out
 * @shrExact is right shift, not allowed to shift 1 bits out

Closes #413