module: Associate unique string with manipulations for better identification.
module: Refactor: User-manipulation modules must return a single function value.
module: Refactor: Rename identifier.

Global table of manipulations:  manipulation  =>  manipulations
module: Refactor: Refrain from using a word iterator.

Patterns are now matched against all words found in a node list in one
run, scanning for words and decomposing them in parallel.  A sequence
of word property tables is passed to the user-manipulation, a table
containing information about all words found in a node list.

Advantages:

  * Performance: Nodes are visited less often.

  * Robustness: Module and user access to nodes is now more separated.
    Manipulating a node list is now more robust.
example: Implement German non-standard hyphenation triple consonant rule.
module: Provide means for debugging patterns.

At the end of a LuaTeX run a list of all words associated with a set
of patterns is written to a file with the patterns applied.  File name
is that of the pattern file plus the extension '.spots'.  A hyphen
within a word indicates a valid spot.
module: Improve word recognition.

Only glyph nodes representing a character with a non-zero lccode are
valid letters of a word.
module: Improve word recognition.

Check for matching word and pattern language.
luatex: Implement rudimentary LaTeX package.
module: Improve word recognition.

Track explicit hyphens in words.  This can be used to imitate TeX's
behaviour of not adding discretionaries in words containing explicit
hyphens.
example: Don't process words containing explicit hyphens.
class: cls_pdnm_spot: Improve function to_word_with_spots().

Letters equal to the spot letter in input, e.g., explicit hyphens, can
now be transformed to a user-defined letter in output.
class: cls_pdnm_spot: Fix rare bug related to minimum spot distances.

Leading and trailing spot minima need to be trimmed to current word
length while zeroing out levels to avoid table word_levels from
getting exessive indices.
example: New: Hyphenate words containing explicit hyphens.
examples: Refactor: More descriptive file and folder names.