Some proofs are failing in the standard library.

[kape1395]

For example, these are failing in library/SequenceTheorems_proofs.tla:

• ConcatSimplifications
• SubSeqProperties
• SubSeqEmpty
• HeadTailAppend
• SequenceEmptyOrAppend

Unsure when the regression happened.
These proofs should probably be checked as part of the test suite.

[muenchnerkindl]

Thanks Karolis, will look into this. I have already started updating some of the other library modules.

[ahelwer]

This was fixed in #217