Replace slow

[Btimes2]

Replace is slow on Windows 10, WinMerge 2.14.6.
For example, when I compared two texts of 18.000 words, each word in different rows.
The older version of the file used a slightly different spelling in many thousands of rows. I only noticed that after loading it in WinMerge, so I tried to replace the old spelling with the new one in WinMerge, to compare the actual content and not the spelling.

Replacing one word in 18.000 rows takes about 1 second in most text editors on my computer, but for WinMerge it took a full minute.

Could it be that WinMerge tries to compare the texts each time any change occures, including every steps of a replace all command? If so, then this could be optimized.

[sdottaka]

Fixes to commit fed6672, 7a7050e, 593cbbb, and f73ddf7 allow replacement operations that used to take about 20 seconds to complete to be completed in less than a second.