mt32emu_qt:
- Fixed incorrect handling of some rarely used control messages in ALSA MIDI driver
In mt32emu_qt:
- Added support for using different sample rates in audio drivers using sample rate conversion.
  It is still preferable to use generic sample rate of MT-32 compatible units 32000 Hz and sample rate conversion
  should be used if a different sample rate is necessary (e.g. audio system doesn't support 32000 Hz) or deliberate.
  For best performance, libsoxr is supported. Libsamplerate is also supported as it is widely available.
  As a worst case, the integrated linear interpolator can be used (it's fast but the quality...).
In mt32emu_qt:
- PortAudio driver now displays corresponding error description if it fails to open
In mt32emu_qt:
- QSynth is now properly closed if SynthRoute fails to start an AudioStream
In mt32emu_qt:
- Fixed output volume when using float samples to correspond the integer samples mode
In mt32emu_qt:
- Messages from test MIDI driver now properly handled when sample rate changes
- Adding a resampler to libmt32emu is no longer a goal. It is advised to use an external sample rate conversion library when there is a need.
Remove incorrect NULL checks.

In well-defined C++ code references can never be bound to dereferenced NULL
pointers. Thus, compilers can assume that the address a reference points at is
always non-NULL. The reason is that if this happens, the behavior is undefined
from now on. Thus, the compiler can do as it pleases. As a result, compilers
might simply remove checks like the ones removed here.

clang's "-Wtautological-undefined-compare" warning option can be used to spot
such issues.
Merge pull request #19 from lordhoto/undefined-behavior-check

Remove incorrect NULL checks.
- Removed unused obsolete data
- Wrapped static constants in ROMInfo to avoid usage of global constructor
LV2 support [wip]

Add a Munt LV2 plugin.
Currently this duplicates the resampler.
Update readme for LV2