Infer alignment IDs for sentences and divs

[mlj]

Currently only objects whose alignment IDs are set explicitly upstream (for whatever reason) have their alignment IDs set in PROIEL XML. This behaviour is not obvious to end users who may expect to find alignment indicated on all objects. Given that we can easily infer alignment of sentences and div elements from token alignments, we should consider adding them in post-processing or having upstream fill them in automatically.

[mlj]

Divs now have inferred alignments whenever necessary. This leaves only a few divs without any alignment IDs. In latin-nt we are missing some from unannotated parts but also some annotated parts. We should look into why this has happened:

    <div id="542">
    <div id="543">
    <div id="545">
    <div id="548">
    <div id="549">
    <div id="551">
    <div id="553">
    <div id="554">
    <div id="555">
    <div id="556">
    <div id="558">
    <div id="559">
    <div id="561">
    <div id="563">
    <div id="564">
    <div id="565">
    <div id="566">
    <div id="568">
    <div id="569">
    <div id="570">
    <div id="571">
    <div id="572">
    <div id="591">

The other NTs are complete except that the Gothic NT has incipits and explicits that of course are unaligned. (In Marianus these are unannotated and therefore do not appear in releases.) We should consider merging such divs with the actual text divs to eliminate.

    <div id="693">
    <div id="710">
    <div id="711">
    <div id="755">
    <div id="770">
    <div id="771">
    <div id="785">
    <div id="786">
    <div id="793">
    <div id="794">
    <div id="801">
    <div id="810">
    <div id="815">
    <div id="816">
    <div id="820">
    <div id="821">
    <div id="828">
    <div id="833">

[mlj]

This is now included in release 20180408.

Keeping this open until we have all issues with alignment-id on div solved.