Add marksAndBreaks.ily: definition of structure (85 min)

Double barline engraver (after time sig changes) should be added
(from oll-lib).
A few manual double barlines should be checked after adding the engraver.
Add marks-and-breaks.ly

Reference 'part' with the line breaking of the original score and all rehearsal marks

TODO: Add performance indications
marksAndBreaks: Update origLineBreak

orignLineBreak now sets the shortInstrumentName of the next system to "".
This gives a better visual indicator of the fact that there is an additional break
Add roman numerals conversion snippet

This is a conversion routine between integers and roman numerals.
This may be useful for numbering variables with roman numerals.

For now it is a Frescobaldi snippet, but it can easily be changed to a
normal Python function.
I don't know yet how I can make it process a whole document. So probably it will be better to be used inside a regular Python script that writes .ly or .ily files

Next step to be done would be to implement a sorting mechanism
Break marksAndBreaks into chunks

Now the music is separated in small chunks, each ending with a rehearsal mark.
So far it is an invalid file because the variables aren't named.
I will do this with a Python script based on the Frescobaldi snippet from the previous commit
Add romannumerals.py

Python unit with int_to_roman and roman_to_int conversion routines.
Used for automatic numbering of section variables
Clean up marksAndBreaks.ily

Make some things more consistent prior to procesing it with a script.
Add number-variables-roman.py

This is a one-time utility script to process marksAndBreaks.ily

This file had been broken to invalid chunks through search&replace
in 53e9857f0359325125bc09d968539d12d6896132

The script numbers the invalid variables with roman numerals.
And it inserts a \time at the beginning of each variable
(the time signature being the last earlier time signature in the file)
Add marksAndBreaks_Roman.ily

This is the result of processing the original marksAndBreaks
with number-variables-roman.py
Change marksAndBreaks_Roman to MultiMeasureRests

Instead of spacer rests the file has now MultiMeasureRests.
This will make it possible to use the variables as placeholder sections
in the final score
.gitignore: *.pyc
Merge branch 'marksandbreaks'