Fix typos in comments and string constants.
Typo in org.csstudio.dct.ui: isCaseSensetiv(), etc.
Typo in org.csstudio.dct: Avoidiance.
Typo in org.csstudio.diag.epics{,.pvmanager}.pvtree: UnkownPVType.
Typo pvParamter (local var only).
typo: PROP_(SRC|TGT)_CONNETIONS in AbstractWidgetModel, AbstractBaseEditPart.
typo: avaliable in StringListSelectionWidget.
typo: setupRelDispUnkownElement in ADLTestObjects, RelatedDisplayItemTest.
typo: SCRIPT_PARAMTER_DESCRIPTIONS in ScriptedRule
typo: testReleaseUnkown in RefCountMapUnitTest
typo: UNKOWN in AbstractProxyImpl
typo: connecionPayload in MultiplexedChannelHandler
typo: disonnecting
more typos in string constants, comments, etc.
typo: alarm_notifer in Application.
typo: tranformToISeverity in EPICSArchiveReader
typo: UNKNOW in Alarm
typo: lenght in ContentProposalList
typo: maxLineLenght in TooltipContent, TooltipDataHandler
typo: lenght in SSStyledText