feature 857: Regex search and replace

- Implemented basic regex search and replace for tables.
- Added a checkbox to use regex in 'Find and Replace' view.
- Fixed some tests for this feature

Signed-off-by: Nisarg Jhaveri <nisarg.jhaveri@students.iiit.ac.in>
Improve message and make it translatable

Signed-off-by: Marc Delisle <marc@infomarc.info>
Update po files
Merge pull request #1334 from nisargjhaveri/feature_857

feature 857: Regex search and replace
ChangeLog entry

Signed-off-by: Marc Delisle <marc@infomarc.info>
Fix coding style

Signed-off-by: Marc Delisle <marc@infomarc.info>
Update po files
Unused code

Signed-off-by: Marc Delisle <marc@infomarc.info>
Fix coding style

Signed-off-by: Marc Delisle <marc@infomarc.info>
Remove old tests

Signed-off-by: Marc Delisle <marc@infomarc.info>
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Merge remote-tracking branch 'origin/master'
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