Added copy() to FITS data read to avoid memmap error on Mac seen in astrolib version.
Refactored codes to integrate modeling. Tests are passing in Python 2.7.5, 3.2, 3.3, and 3.4, and have 95 percent coverage. PEP8 check done. Doc updated.
Merge pull request #62 from pllim/modeling-brainstorming

Major refactoring to use modeling