Fixed spelling errors

Fixed some spelling errors found by Lintian while checking the Debian
package of LMMS. Thanks to Patrick Winnertz for pointing out this issue.

src/core/AutomatableModel.cpp

@@ -145,7 +145,7 @@ void AutomatableModel::loadSettings( const QDomElement & _this,
 			p->loadSettings( node.toElement() );
 			setValue( p->valueAt( 0 ) );
 			// in older projects we sometimes have odd automations
-			// with just one value in - eliminate if neccessary
+			// with just one value in - eliminate if necessary
 			if( !p->hasAutomation() )
 			{
 				delete p;

src/core/Mixer.cpp

@@ -393,7 +393,7 @@ sampleFrameA * Mixer::renderNextBuffer()
 
 
 
-// removes all play-handles. this is neccessary, when the song is stopped ->
+// removes all play-handles. this is necessary, when the song is stopped ->
 // all remaining notes etc. would be played until their end
 void Mixer::clear()
 {

src/core/midi/MidiClient.cpp

@@ -265,7 +265,7 @@ void MidiClientRaw::processOutEvent( const midiEvent & _me,
 							const midiTime & ,
 							const MidiPort * _port )
 {
-	// TODO: also evaluate _time and queue event if neccessary
+	// TODO: also evaluate _time and queue event if necessary
 	switch( _me.m_type )
 	{
 		case MidiNoteOn:

src/core/song.cpp

@@ -339,7 +339,7 @@ void song::processNextBuffer()
 		return;
 	}
 
-	// check for looping-mode and act if neccessary
+	// check for looping-mode and act if necessary
 	timeLine * tl = m_playPos[m_playMode].m_timeLine;
 	bool check_loop = tl != NULL && m_exporting == false &&
 				tl->loopPointsEnabled() &&

src/core/track.cpp

@@ -1,5 +1,5 @@
 /*
- * track.cpp - implementation of classes concerning tracks -> neccessary for
+ * track.cpp - implementation of classes concerning tracks -> necessary for
  *             all track-like objects (beat/bassline, sample-track...)
  *
  * Copyright (c) 2004-2009 Tobias Doerffel <tobydox/at/users.sourceforge.net>

src/gui/automation_editor.cpp

@@ -223,7 +223,7 @@ automationEditor::automationEditor() :
 			"'Shift+E' on your keyboard to activate this mode." ) );
 	m_selectButton->setWhatsThis(
 		tr( "Click here and select-mode will be activated. In this "
-			"mode you can select values. This is neccessary "
+			"mode you can select values. This is necessary "
 			"if you want to cut, copy, paste, delete, or move "
 			"values. You can also press 'Shift+S' on your keyboard "
 			"to activate this mode." ) );

src/gui/widgets/InstrumentSoundShapingView.cpp

@@ -58,7 +58,7 @@ InstrumentSoundShapingView::InstrumentSoundShapingView( QWidget * _parent ) :
 	m_targetsTabWidget->setWhatsThis(
 		tr( "These tabs contain envelopes. They're very important for "
 			"modifying a sound, in that they are almost "
-			"always neccessary for substractive synthesis. For "
+			"always necessary for substractive synthesis. For "
 			"example if you have a volume envelope, you can set "
 			"when the sound should have a specific volume. "
 			"If you want to create some soft strings then your "