Super long lines slow down SynEdit

[pyscripter]

Lines much longer that 10K slow down caret positioning and file looading.

Discussed in #157

^{Originally posted by pyscripter February 6, 2022}
@MShark67
I have introduced a parallel for loom (from System.Threading) in the calculation of MaxWidth. Could you please test it with you 250K file and check whether it makes a difference in performance?
Thanks!

[pyscripter]

Implemented a switch to Wordwrap when lines greater than 10000 characters long are inserted,