New SnareMarch preset and updated KickPower

The snare sounds like it would be used for marching. If you can make it
brighter without making it sound funny, please do...

The kick was too dark for general purpose. Shortened it, raised it in
the frequency range and added more noise.
Update FxMixer.cpp

prevent double adding of jobs
Check major/minor version before setting theme directory
Merge pull request #1442 from tresf/stable-1.1

Check major/minor version before setting theme directory
Fix scroll bar gap

Closes #1437
Bump DualFilter high cutoff to 20k

Closes #1395.
Merge pull request #7 from LMMS/stable-1.1

merge LMMS/lmms
Proposed fix for #1432 LB302 preset preview audio cut-off
Merge pull request #1433 from Sti2nd/stable-1.1

New SnareMarch preset and updated KickPower

No objections after a week, merging. -Tres
Proposed fix for #1411 Crash on LB302 preset preview .
Proposed fix for 1450 Mem leak in sample-track
Merge pull request #1451 from curlymorphic/i1450

Proposed fix for 1450 Mem leak in sample-track
Merge pull request #1449 from curlymorphic/I1432

Proposed fix for issue 1432 LB302 preset preview audio cut-off
Update Carla plugin to latest API
Fix build when using old linux systems
Bump version
Merge pull request #1453 from falkTX/stable-1.1

Fix for updated Carla API, and fix build on old linux systems
Update opl2instrument.cpp
Update papu_instrument.cpp
Remove RackView widget before deleting the ChannelView

Fixes the following two errors I spotted using valgrind:
When deleting a channel;
==936== Invalid read of size 8
==936==    at 0x56FA1D: FxMixerView::deleteChannel(int) (FxMixerView.cpp:374)
==936==    by 0x60E9A79: QMetaObject::activate(QObject*, QMetaObject const*, int, void**) (in /usr/lib/x86_64-linux-gnu/libQtCore.so.4.8.6)
==936==    by 0x5216BF1: QAction::triggered(bool) (in /usr/lib/x86_64-linux-gnu/libQtGui.so.4.8.6)
==936==    by 0x52185C2: QAction::activate(QAction::ActionEvent) (in /usr/lib/x86_64-linux-gnu/libQtGui.so.4.8.6)
==936==  Address 0x14d51b90 is 32 bytes inside a block of size 40 free'd
==936==    at 0x4C2C2E0: operator delete(void*) (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==936==    by 0x56F9ED: FxMixerView::deleteChannel(int) (FxMixerView.cpp:370)
==936==    by 0x60E9A79: QMetaObject::activate(QObject*, QMetaObject const*, int, void**) (in /usr/lib/x86_64-linux-gnu/libQtCore.so.4.8.6)
==936==    by 0x5216BF1: QAction::triggered(bool) (in /usr/lib/x86_64-linux-gnu/libQtGui.so.4.8.6)

When loading a new project after adding some channels:
==936== Invalid read of size 8
==936==    at 0x570785: FxMixerView::refreshDisplay() (FxMixerView.cpp:202)
==936==    by 0x4B590E: Song::clearProject() (Song.cpp:740)
==936==    by 0x4B7885: Song::createNewProject() (Song.cpp:817)
==936==    by 0x60E9A79: QMetaObject::activate(QObject*, QMetaObject const*, int, void**) (in /usr/lib/x86_64-linux-gnu/libQtCore.so.4.8.6)
==936==  Address 0x56a12ab0 is 32 bytes inside a block of size 40 free'd
==936==    at 0x4C2C2E0: operator delete(void*) (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==936==    by 0x57075B: FxMixerView::refreshDisplay() (FxMixerView.cpp:201)
==936==    by 0x4B590E: Song::clearProject() (Song.cpp:740)
==936==    by 0x4B7885: Song::createNewProject() (Song.cpp:817)