Issue #124, case 0: Fixed long standing bug with inconsistent cursor position after select-word
If there's a selection, cursor position (`cursorLine` / `cursorCol` instvars)
are required to be same as either selection start or selection end.
#selectWordAtLine:col: did not update cursor position accordingly,
leading to assertion failure. This bug has been there for a loong
time. My bad, I was too lazy to fix it, until today...
https://swing.fit.cvut.cz/projects/stx-jv/ticket/124