Remove unnecessary deprecated nvd3 files

Getting rid of these will reduce the size of the project, allow faster uploads to shinyapps.io, and make it easier for others to see what is going on.
Remove shinyapps.io folders from git control
Set gitignore for shinyapps folders
Implement Line With Focus Chart

Mostly the same as linechart with some key differences.
- The method for detecting disabled series relies on traversing the DOM of the SVG element.  This is different from linechart in that linechart has a state.chart.state().disabled method that stores the enabled/disabled state of each series.  Line With Focus Chart does not have this method.  So we have to look through the DOM, find the nv-legend move in two child elements, and check whether the series element has a class attribute 'disabled'.

- The next major difference is in the xDomain behavior.  the entire point of using a line with focus chart is so that the user can adjust the xDomain on the 'focused' chart.  To that end, the xDomain functionality was striped from the linewithfocuschart-binding.js functions.  To enable some compatibilty with linechart, the relevant parts of code were left in place in the linewithfocuschart.R functions.  This means that if there is an xDomain passed to renderLineWithFocusChart, the input dataframe will be trimmed so that the data passed to the nvd3 functions will not include anything outside xDomain.  This has the effect that the starting position of the focus and 'global' charts will be trimmed to xDomain.  Further 'focusing' will be allowed through the built in features of the line with focus chart.

Features that are preserved between linechart and linewithfocuschart are:
- Plot series as lines, points, both, or none.
- Manually assign colors to the graph, passed as rgb in vector form, R color names, or Hex.
- Adjust yDomain.
- Disabled status is preserved through Shiny reactive updates.