make syntax compatible with TLAPM (#120)

* make syntax compatible with TLAPM

Signed-off-by: Stephan Merz <stephan.merz@loria.fr>

* reformulation of comment on syntax not supported by TLAPS

Signed-off-by: Stephan Merz <stephan.merz@loria.fr>

---------

Signed-off-by: Stephan Merz <stephan.merz@loria.fr>

two more theorems about folds (#119)

Signed-off-by: Stephan Merz <stephan.merz@loria.fr>

Update SVGSerialize to use three-digit zero-padding for frame numbers…

… in generated SVG filenames for improved lexicographic sorting.

Two digits turned out to be too conservative.  For example, the solution to the SlidingPuzzle.tla of the TLA+ examples is longer.

Signed-off-by: Markus Alexander Kuppe <github.com@lemmster.de>

more theorems about folds (#118)

* more theorems about folds

Signed-off-by: Stephan Merz <stephan.merz@loria.fr>

* more theorems on folds

Signed-off-by: Stephan Merz <stephan.merz@loria.fr>

* theorems for SumFunction

Signed-off-by: Stephan Merz <stephan.merz@loria.fr>

* align statement of ReverseSubSeq

Signed-off-by: Stephan Merz <stephan.merz@loria.fr>

---------

Signed-off-by: Stephan Merz <stephan.merz@loria.fr>

Remove tabs from VectorClocks.tla (#117)

TLAPM does not like tabs

Signed-off-by: Andrew Helwer <ahelwer@pm.me>

Merge pull request #116 from tlaplus/fold_proofs

theorem library for fold operators

Do not require CSV read/write operations to be state level.

Constant level is sufficient and allows TLC to cache the results.

Signed-off-by: Markus Alexander Kuppe <github.com@lemmster.de>

Add new string deserialize test

Signed-off-by: fhackett <fhackett.py@gmail.com>

Enhance SVGSerialize to use zero-padded frame numbers for consistent …

…file sorting.

(Up to 99 frames seems reasonable)

The following snippet produces the expected result:
```bash
convert -delay 100 -loop 0 *.svg animation.gif
```

[Feature]

Signed-off-by: Markus Alexander Kuppe <github.com@lemmster.de>

Add SVGDoc and SVGSerialize functions for SVG document creation and

serialization.

[Feature]

Signed-off-by: Markus Alexander Kuppe <github.com@lemmster.de>