Update CHANGELOG.txt

Update CHANGELOG.txt

issue audacity#2119: Data loss on joining clips

Joining clips using the Join command (Ctrl+J) can cause data in preceeding clips to be silenced.

Fix: In WaveTrack::Join(), the initial value of t should be PlayStartTime of the first clip, not SequenceStartTime.

Fixes WaveTrack::ClearAndPaste

ClearAndPaste now also is able to preserve trimmed data and old clip names at split points

Fix envelope drawing again

Update audacity.pot and .po files for 3.1.0

Fix bug 1571 (audacity#1701)

* Fix bug 1571.

Convert to C locale decimal point for stable parsing.

* [Review] Add recommendations.

Revert "Bug 1686 - Equalization effects ignore and remove any amplitu…

…de envelope"

This reverts commit 58adb94.

pl.po - very important fix

File pl.po needs fix, because strings with "fuzzy" are untranslated in program.

Greetings,
Gootector

Fixes crash in ErrorReportDialog