Simplified UI

Update of the user interface with the goal of making JHelioviewer easier and more intuitive to use. Key features:
a) Movie layers will be grouped by time range and automatically linked to be displayed jointly.
b) The user accesses movies by specifying the time range and cadence once when selecting the first layer. All subsequent layers will be added with the set values for t_start, t_end and delta_t. All layers will are grouped into a movie tab.
c) Opening of files without the Helioviewer API: All Images without time stamp will be grouped into an image tab. Movies with >80% overlap with the time range of an existing movie tab will be opened in this tab (i.e. >80% of the time range covered by the new movie is contained within the time range of the existing tab), movies with <20% overlap will be opened in a new tab, for movies with 20-80% overlap, the user will be asked whether a new tab should be opened or an existing one be used.
d) For remote files accessed via JPIP, up to three tabs can be used (to limit use of JPIP server resources).