Develop basic documentation

[martynpclark]

No description provided.

[bartnijssen]

Added:

• readme.md
• in docs/howto:
  • For model users:
    • How to install SUMMA on Mac OS X
  • For developers:
    • Common Git commands
    • How to use Git to work with SUMMA
    • Proposed workflow for Git

Still needed:

• Description of SUMMA input and configuration files
• Description of SUMMA output files
• How to run SUMMA
• Sample application

[bartnijssen]

• for sample application and how to run SUMMA: link to readme in summa/settings
• for description of SUMMA I/O and config: Look at summer school documentation

[bartnijssen]

I am leaving the description of the SUMMA output files along for now and will just refer to the plotting scripts in the verification directory. Better documentation will remain an open issue for SUMMA, but I am concerned that I'm delaying at least a soft launch. My hope is that once we launch we can recruit others to the effort.