Fix #36451 : Alla breve forced to 2/2

Basically reverts commit https://github.com/musescore/musescore/commit/7ab8acd which was intended to fix issue http://musescore.org/en/node/14548 (apparently no longer needed)

Fix code is kept but commented out, with detailed comment and a small addition, in case the originanl issue pops up again in the future.

See http://musescore.org/en/node/36541 for more details, score samples and discussion.
fix #20122: [Linux] Export as pdf impossible, cannot determine file type
fix #36731
fix regressions / mtest
make message dialog icons bigger
fix #32911: Tempo marking added by the New Score Wizard doesn't follow text
Comment removed.
fix capitalisation of various strings in dialogs

to comply with
http://musescore.org/developers-handbook/design/user-interface-text-style-guide.
Also change "Spatium" and "Space" to "Staff space" (where user visible),
see also discussion at http://musescore.org/en/node/36891.
fix #36606: No sequencer and audio drivers if runned with '-s'
fix #18798: stems/rests not reset on undo exchange voices
Merge pull request #1385 from Jojo-Schmitz/capitalization

Some more text fixes
Merge pull request #1389 from Igevorse/bugs1

fix #36606: No sequencer and audio drivers if runned with '-s'
Merge pull request #1390 from MarcSabatella/18798-undo-exchange

fix #18798: stems/rests not reset on undo exchange voices
Merge pull request #1387 from jpfleury/32911-follow-text

fix #32911: Tempo marking from New Score Wizard doesn't follow text
Typo error - Reset element Ppoperties

Changed:
Reset element Properties
Merge pull request #1392 from Gootector/patch-10

Typo error - Reset element Ppoperties
Merge pull request #1384 from jpfleury/20122-export-pdf

fix #20122: [Linux] Export as pdf impossible, cannot determine file type
Merge pull request #1375 from mgavioli/Fix_36451_Alla_breve_forced_to_2_2

Fix #36451 : Alla breve forced to 2/2
fix some typos from PR #1385
Merge pull request #1394 from Jojo-Schmitz/capitalization

fix some typos from PR #1385