Removed runtime styling for hints (#40).

There is no need to change the hints style properties during runtime. So this
settings are removed. But on the other side all hinted elements and hint label
have now classes to style them via user style. Following style is the default
used for the hints.

._hintLabel {
    position: absolute;
    z-index: 100000;
    font-family: monospace;
    font-weight: bold;
    font-size: 10px;
    color: #000;
    background-color: #fff;
    margin: 0;
    padding: 0px 1px;
    border: 1px solid #444;
    opacity: 0.7
}
._hintElem {
    background-color: #ff0 !important;
    color: #000 !important
}
._hintElem._hintFocus{
    background-color: #8f0 !important
}
._hintLabel._hintFocus{
    opacity: 1
}