Directory struct

[lemmatum]

Added an initial directory structure for SpectroscoPy.

• atomic = database queries and interface for atomic data (e.g. NIST, CHIANTI)
• diagnostics = stuff useful for diagnostics (e.g. Henke filter queries, calibrations, dispersion calculations, background correction tools)
• examples = place to show off how to do cool stuff with these tools
• lineshape = database queries and interface for lineshape data
• opacity = database queries and interface for opacity data
• simulation = tools for simulating spectra (e.g., simple Saha-Boltzmann LTE using NIST atomic database, full-blown collisional-radiative model)
• visualization = handy tools for plotting and comparing spectra, line ratios, etc.