..channel.views: refactor line2dplot to ChannelLinePlot

Change-Id: Id55ccaa5b28b47eab69856962e88362da1a0b0ef
..channel.*: refactor line2DPlot to ChannelLinePlot for swt and BOY
widgets

Change-Id: Ieea032d49efed0cb572aed411b552f36f9f4f8e0
..channel.opiwidget: renaming the widget, keeping the widgetId the same
for compatibility reasons.

Change-Id: I8d7d235ddf529949dfda961f84efe9b8c3c99412
..channel.widget: updating the help documentation.

Change-Id: I8e7776ad7ae831228ee5041a39bbbf06c36a3a19