fixing issue in glyph_line example where axes were not showing up
Renaming glyph_line.py to line.py
removing glyph_file_output2 demo b/c it is superseded by examples in plotting/
Fixing square marker to have the additional dataspecs per BokehJS
Adding more full-featured show() command in plotting.py, improving handling of dataspecs in scatter() to also handle the "size" parameter
removing generic plot() command for now