Reorganized source files into modules
Removed all the work from the main file, and distributed functions
and classes logically into a set of modules. Added a prototype for
the picker widget.

Added copyright to UI files.
Added a test image to the debug folder.
Added specificity to the roadmap, particularly v0.1.

new file:   debug/test_image_KS.tif
modified:   roadmap.md
renamed:    term-peeper.py -> term-peeper/mainwindow.py
new file:   term-peeper/modis.py
new file:   term-peeper/termpeeperIO.py
modified:   ui/data_download_dialog.ui
renamed:    ui/test_1.ui -> ui/main_window.ui