improve word detection

[ilf]

resolution=word seems to ignore punctiation (and Umlauts), which is not intuitive. Example:

<span class="common">anderen Lä</span><span class="before-change"><del>ndern.</del></span><span class="after-change"><ins>ndern (vgl. foo). </ins></span>

In this case, logically this would be more accurate:

<span class="common">anderen Ländern</span><span class="before-change"><del>.</del></span><span class="after-change"><ins> (vgl. foo).</ins></span>